Method and device for transmitting data in wireless power transmission system

ABSTRACT

The present disclosure relates to a method and a device for transmitting data in a wireless power transmission system. The method for transmitting data by a wireless power transmitter in a wireless power transmission system may comprise the steps of: receiving from a wireless power receiver, within a first control error interval, a first control error packet containing a control error value with respect to power transmitted from the wireless power transmitter; determining the size of a first data packet on the basis of the length of the first control error interval; and transmitting the first data packet to the wireless power receiver.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.17/280,503, filed on Mar. 26, 2021, which is the National Stage filingunder 35 U.S.C. 371 of International Application No. PCT/KR2019/008548,filed on Jul. 11, 2019, which claims the benefit of earlier filing dateand right of priority to Korean Application No. 10-2018-0126992 filed onOct. 23, 2018, the contents of which are all incorporated by referenceherein their entirety.

BACKGROUND OF THE DISCLOSURE Field of the Disclosure

The present disclosure relates to wireless power transmission, and moreparticularly, to a method and apparatus for transmitting data in awireless power transmission system.

Related Art

Wireless power transmission technology is a technology for wirelesslytransmitting power between a power source and an electronic device. Forexample, according to the wireless power transmission technology, abattery of a wireless terminal such as a smartphone or a tablet can becharged simply by putting the wireless terminal on a wireless chargingpad, and thus, higher mobility, convenience, and stability than those ina conventional wired charging environment using a wired chargingconnector can be provided. The wireless power transmission technology isreceiving attention as a technology that will replace the conventionalwired power transmission environment in various fields such as electricvehicles, various wearable devices such as Bluetooth earphones and 3Dglasses, home appliances, furniture, underground facilities, buildings,medical devices, robots, and leisure in addition to wireless charging ofwireless terminals.

Wireless power transmission is also called contactless powertransmission, no point of contact power transmission, or wirelesscharging. A wireless power transmission system may include a wirelesspower transmitter that supplies electric energy through wireless powertransmission and a wireless power receiver that receives the electricenergy wirelessly supplied from the wireless power transmitter andsupplies power to a power-receiving device such as a battery cell.

The wireless power transmission technology includes various methods suchas a method of transmitting power through magnetic coupling, a method oftransmitting power through a radio frequency (RF), a method oftransmitting power through microwaves, and a method of transmittingpower through ultrasonic waves. Methods based on magnetic coupling areclassified into magnetic induction and magnetic resonance. Magneticinduction is a method of transmitting energy using current induced to acoil of a reception side due to magnetic fields generated in a coilbattery cell of a transmission side according to electromagneticcoupling of a coil of the transmission side and the coil of thereception side. Magnetic resonance is similar to magnetic induction inthat magnetic fields are used. However, magnetic resonance differs frommagnetic induction in that resonance occurs when a specific resonancefrequency is applied to a coil of a transmission side and a coil of areception side, and thus, energy is transmitted according to aphenomenon that magnetic fields are concentrated on both ends of thetransmission side and the reception side.

In general, the magnetic induction scheme operates according to awireless power consortium (WPC) standard. According to the WPC standard,a wireless power transmitter and a wireless power receiver maycommunicate with each other. In this case, data communication from thewireless power transmitter to the wireless power receiver uses afrequency shift keying (FSK) scheme, and data communication from thewireless power receiver to the wireless power transmitter uses anamplitude shift keying (ASK) scheme. Further, according to the WPCstandard, a control error packet (CEP) may be transmitted every 250 msin a power transmission step from the wireless power receiver to thewireless power transmitter. Data can be transmitted at a control errorinterval. However, as such, since a time capable of transmitting data islimited due to the control error interval, an amount of data that can betransmitted within a specific period of time is limited. Further,although communication from the wireless power transmitter to thewireless power receiver is achieved with FSK, there is a limitation intransmitting a large amount of data since the FSK is characterized inhaving a slow transfer rate. In addition, since a data packettransmitted at the control error interval has a fixed length, when thecontrol error interval is shorter than the length of the data packet dueto a load change caused by vibration, shock, or the like, data cannot betransmitted at that interval. Therefore, a process of exchanging a lotof data between the wireless power transmitter and the wireless powerreceiver is necessary to utilize an additional function such as a futureauthentication process. However, there is a problem in that it takes along time when using the conventional technology.

SUMMARY

The present disclosure provides a data transmission method and apparatusin which data can be transmitted even if a load changes during wirelesscharging.

The present disclosure also provides a data transmission method andapparatus in which a lot of data can be transmitted within a shortperiod of time.

According to an aspect of the present disclosure, a method oftransmitting data by a wireless power transmitter in a wireless powertransmission system may include receiving, from a wireless powerreceiver within a first control error interval, a first control errorpacket including a control error value for power transmitted from thewireless power transmitter, determining a size of a first data packet,based on a length of the first control error interval, and transmittingthe first data packet to the wireless power receiver.

In an aspect, the length of the first data packet may be determinedbased on a size of a data packet received from the wireless powertransmitter before the first control error packet is received.

In another aspect, the size of the first data packet may vary dependingon the length of the first control error interval.

In another aspect, after the receiving, the method may further includereceiving a second data packet from the wireless power receiver withinthe first control error interval, wherein the size of the first datapacket is determined based on a size of the first control error packetand a length of the second data packet.

In another aspect, the first data packet may be an auxiliary datatransport (ADT) data packet, and the second data packet may be a datastream response (DSR) data packet.

In another aspect, after the receiving, the method may further includechanging a length of a second control error interval, based on at leastone of the control error value and the length of the first control errorinterval, and transmitting a second data packet including information onthe second control error interval to the wireless power receiver.

In another aspect, the changing may further include increasing thelength of the second control error interval based on that the controlerror value is within a pre-set range.

In another aspect, the changing may further include decreasing thelength of the second control error interval based on that if the controlerror value is out of a pre-set range.

In another aspect, after the transmitting, the method may furtherinclude receiving a response packet for the first data packet from thewireless power receiver within a second control error interval,adjusting a size of a third data packet, based on the response packet,and transmitting the third data packet to the wireless power receiver.

According to another aspect of the present disclosure, a method oftransmitting data by a wireless power receiver in a wireless powertransmission system may include transmitting, to a wireless powertransmitter within a first control error interval, a first control errorpacket including a control error value for power transmitted from thewireless power transmitter, determining a size of a first data packet,based on a length of the first control error interval, and transmittingthe first data packet within the first control error interval to thewireless power transmitter.

In an aspect, the size of the first data packet may vary depending onthe length of the first control error interval.

In another aspect, before the determining, the method may furtherinclude determining the length of the first control error interval,based on the control error value, and transmitting to the wireless powertransmitter a second data packet including information on the firstcontrol error interval.

In another aspect, the changing may further include increasing thelength of the first control error interval based on that the controlerror value is within a pre-set range.

In another aspect, the changing may further include decreasing thelength of the first control error interval based on that the controlerror value is out of a pre-set range.

In another aspect, at least one of the first data packet and the seconddata packet may be an auxiliary data transport (ADT) data packet.

EFFECTS OF THE DISCLOSURE

According to the present disclosure, a data packet can be transmittedeven if a load changes during wireless charging, and more data can betransmitted within a shorter period of time, compared to theconventional case.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a wireless power system (10) according toan exemplary embodiment of the present disclosure.

FIG. 2 is a block diagram of a wireless power system (10) according toanother exemplary embodiment of the present disclosure.

FIG. 3 a shows an exemplary embodiment of diverse electronic devicesadopting a wireless power transfer system.

FIG. 3 b shows an example of a WPC NDEF in a wireless power transfersystem.

FIG. 4 a is a block diagram of a wireless power transfer systemaccording to another exemplary embodiment of the present disclosure.

FIG. 4 b is a diagram illustrating an example of a Bluetoothcommunication architecture to which an embodiment according to thepresent disclosure may be applied.

FIG. 4 c is a block diagram illustrating a wireless power transfersystem using BLE communication according to an example.

FIG. 4 d is a block diagram illustrating a wireless power transfersystem using BLE communication according to another example.

FIG. 5 is a state transition diagram for describing a wireless powertransfer procedure.

FIG. 6 shows a power control method according to an exemplary embodimentof the present disclosure.

FIG. 7 is a block diagram of a wireless power transmitter according toanother exemplary embodiment of the present disclosure.

FIG. 8 shows a wireless power receiver according to another exemplaryembodiment of the present disclosure.

FIG. 9 shows a communication frame structure according to an exemplaryembodiment of the present disclosure.

FIG. 10 is a structure of a sync pattern according to an exemplaryembodiment of the present disclosure.

FIG. 11 shows operation statuses of a wireless power transmitter and awireless power receiver in a shared mode according to an exemplaryembodiment of the present disclosure.

FIG. 12 illustrates a wireless charging certificate format according toan embodiment.

FIG. 13 illustrates a capability packet structure of a wireless powertransmitter according to an embodiment.

FIG. 14 illustrates a configuration packet structure of a wireless powerreceiver according to an embodiment.

FIG. 15 illustrates a data stream of an application level between awireless power transmitter and a wireless power receiver according to anembodiment.

FIG. 16 illustrates a method in which a wireless power transmitter and awireless power receiver exchange data according to an embodiment.

FIG. 17 is a flowchart illustrating a process in which a wireless powerreceiver transmits data to a wireless power transmitter.

FIG. 18 is a flowchart illustrating a process in which a wireless powerreceiver transmits data to a wireless power transmitter according to anembodiment.

FIG. 19 is a flowchart illustrating a method in which a wireless powertransmitter and a wireless power receiver exchange data according to anembodiment.

FIG. 20 illustrates a case where an inefficient time in which datacannot be transmitted occurs due to a load transient situation.

FIG. 21 illustrates a method in which a wireless power transmitter and awireless power receiver exchange data in a load transient situationaccording to an embodiment.

FIG. 22 is an exemplary diagram illustrating a case in which aninefficient time where a data packet cannot be transmitted occurs due toa load transient situation while a wireless power receiver transmitsdata to a wireless power transmitter.

FIG. 23 is an exemplary diagram illustrating a method of efficientlytransmitting a data packet even if an inefficient time occurs as shownin FIG. 22 .

FIG. 24 is an exemplary diagram illustrating a case in which aninefficient time where a data packet cannot be transmitted occurs due toa load transient situation while a wireless power transmitter transmitsdata to a wireless power receiver.

FIG. 25 is an exemplary diagram illustrating a method of efficientlytransmitting a data packet even if an inefficient time occurs as shownin FIG. 24 .

FIG. 26 is an exemplary diagram illustrating a process in which awireless power transmitter transmits a data packet to a wireless powerreceiver in a load transient situation according to an embodiment.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

The term “wireless power”, which will hereinafter be used in thisspecification, will be used to refer to an arbitrary form of energy thatis related to an electric field, a magnetic field, and anelectromagnetic field, which is transferred (or transmitted) from awireless power transmitter to a wireless power receiver without usingany physical electromagnetic conductors. The wireless power may also bereferred to as a wireless power signal, and this may refer to anoscillating magnetic flux that is enclosed by a primary coil and asecondary coil. For example, power conversion for wirelessly chargingdevices including mobile phones, cordless phones, iPods, MP3 players,headsets, and so on, within the system will be described in thisspecification. Generally, the basic principle of the wireless powertransfer technique includes, for example, all of a method oftransferring power by using magnetic coupling, a method of transferringpower by using radio frequency (RF), a method of transferring power byusing microwaves, and a method of transferring power by using ultrasound(or ultrasonic waves).

FIG. 1 is a block diagram of a wireless power system (10) according toan exemplary embodiment of the present disclosure.

Referring to FIG. 1 , the wireless power system (10) include a wirelesspower transmitter (100) and a wireless power receiver (200).

The wireless power transmitter (100) is supplied with power from anexternal power source (S) and generates a magnetic field. The wirelesspower receiver (200) generates electric currents by using the generatedmagnetic field, thereby being capable of wirelessly receiving power.

Additionally, in the wireless power system (10), the wireless powertransmitter (100) and the wireless power receiver (200) may transceive(transmit and/or receive) diverse information that is required for thewireless power transfer. Herein, communication between the wirelesspower transmitter (100) and the wireless power receiver (200) may beperformed (or established) in accordance with any one of an in-bandcommunication, which uses a magnetic field that is used for the wirelesspower transfer (or transmission), and an out-band communication, whichuses a separate communication carrier. Out-band communication may alsobe referred to as out-of-band communication. Hereinafter, out-bandcommunication will be largely described. Examples of out-bandcommunication may include NFC, Bluetooth, Bluetooth low energy (BLE),and the like.

Herein, the wireless power transmitter (100) may be provided as a fixedtype or a mobile (or portable) type. Examples of the fixed transmittertype may include an embedded type, which is embedded in in-door ceilingsor wall surfaces or embedded in furniture, such as tables, an implantedtype, which is installed in out-door parking lots, bus stops, subwaystations, and so on, or being installed in means of transportation, suchas vehicles or trains. The mobile (or portable) type wireless powertransmitter (100) may be implemented as a part of another device, suchas a mobile device having a portable size or weight or a cover of alaptop computer, and so on.

Additionally, the wireless power receiver (200) should be interpreted asa comprehensive concept including diverse home appliances and devicesthat are operated by being wirelessly supplied with power instead ofdiverse electronic devices being equipped with a battery and a powercable. Typical examples of the wireless power receiver (200) may includeportable terminals, cellular phones, smartphones, personal digitalassistants (PDAs), portable media players (PDPs), Wibro terminals,tablet PCs, phablet, laptop computers, digital cameras, navigationterminals, television, electronic vehicles (EVs), and so on.

In the wireless power system (10), one wireless power receiver (200) ora plurality of wireless power receivers may exist. Although it is shownin FIG. 1 that the wireless power transmitter (100) and the wirelesspower receiver (200) send and receive power to and from one another in aone-to-one correspondence (or relationship), as shown in FIG. 2 , it isalso possible for one wireless power transmitter (100) to simultaneouslytransfer power to multiple wireless power receivers (200-1, 200-2, . . ., 200-M). Most particularly, in case the wireless power transfer (ortransmission) is performed by using a magnetic resonance method, onewireless power transmitter (100) may transfer power to multiple wirelesspower receivers (200-1, 200-2, . . . , 200-M) by using a synchronizedtransport (or transfer) method or a time-division transport (ortransfer) method.

Additionally, although it is shown in FIG. 1 that the wireless powertransmitter (100) directly transfers (or transmits) power to thewireless power receiver (200), the wireless power system (10) may alsobe equipped with a separate wireless power transceiver, such as a relayor repeater, for increasing a wireless power transport distance betweenthe wireless power transmitter (100) and the wireless power receiver(200). In this case, power is delivered to the wireless powertransceiver from the wireless power transmitter (100), and, then, thewireless power transceiver may transfer the received power to thewireless power receiver (200).

Hereinafter, the terms wireless power receiver, power receiver, andreceiver, which are mentioned in this specification, will refer to thewireless power receiver (200). Also, the terms wireless powertransmitter, power transmitter, and transmitter, which are mentioned inthis specification, will refer to the wireless power transmitter (100).

FIG. 3 a shows an exemplary embodiment of diverse electronic devicesadopting a wireless power transfer system, and FIG. 3 b shows an exampleof a WPC NDEF in a wireless power transfer system.

As shown in FIG. 3 a , the electronic devices included in the wirelesspower transfer system are sorted in accordance with the amount oftransmitted power and the amount of received power. Referring to FIG. 3a , wearable devices, such as smart watches, smart glasses, head mounteddisplays (HMDs), smart rings, and so on, and mobile electronic devices(or portable electronic devices), such as earphones, remote controllers,smartphones, PDAs, tablet PCs, and so on, may adopt a low-power(approximately 5 W or less or approximately 20 W or less) wirelesscharging method.

Small-sized/Mid-sized electronic devices, such as laptop computers,robot vacuum cleaners, TV receivers, audio devices, vacuum cleaners,monitors, and so on, may adopt a mid-power (approximately 50 W or lessor approximately 200 W or less) wireless charging method. Kitchenappliances, such as mixers, microwave ovens, electric rice cookers, andso on, and personal transportation devices (or other electric devices ormeans of transportation), such as powered wheelchairs, powered kickscooters, powered bicycles, electric cars, and so on may adopt ahigh-power (approximately 2 kW or less or approximately 22 kW or less)wireless charging method.

The electric devices or means of transportation, which are describedabove (or shown in FIG. 1 ) may each include a wireless power receiver,which will hereinafter be described in detail. Therefore, theabove-described electric devices or means of transportation may becharged (or re-charged) by wirelessly receiving power from a wirelesspower transmitter.

Hereinafter, although the present disclosure will be described based ona mobile device adopting the wireless power charging method, this ismerely exemplary. And, therefore, it shall be understood that thewireless charging method according to the present disclosure may beapplied to diverse electronic devices.

A standard for the wireless power transfer (or transmission) includes awireless power consortium (WPC), an air fuel alliance (AFA), and a powermatters alliance (PMA).

The WPC standard defines a baseline power profile (BPP) and an extendedpower profile (EPP). The BPP is related to a wireless power transmitterand a wireless power receiver supporting a power transfer of SW, and theEPP is related to a wireless power transmitter and a wireless powerreceiver supporting the transfer of a power range greater than SW andless than 30 W.

Diverse wireless power transmitters and wireless power receivers eachusing a different power level may be covered by each standard and may besorted by different power classes or categories.

For example, the WPC may categorize (or sort) the wireless powertransmitters and the wireless power receivers as PC-1, PC0, PC1, andPC2, and the WPC may provide a standard document (or specification) foreach power class (PC). The PC-1 standard relates to wireless powertransmitters and wireless power receivers providing a guaranteed powerof less than SW. The application of PC-1 includes wearable devices, suchas smart watches.

The PC0 standard relates to wireless power transmitters and receiversproviding a guaranteed power of SW. The PC0 standard includes an EPPhaving a guaranteed power ranges that extends to 30 W. Although in-band(IB) communication corresponds to a mandatory communication protocol ofPC0, out-of-band (OB) communication that is used as an optional backupchannel may also be used for PC0. The wireless power receiver may beidentified by setting up an OB flag, which indicates whether or not theOB is supported, within a configuration packet. A wireless powertransmitter supporting the OB may enter an OB handover phase bytransmitting a bit-pattern for an OB handover as a response to theconfiguration packet. The response to the configuration packet maycorrespond to an NAK, an ND, or an 8-bit pattern that is newly defined.The application of the PC0 includes smartphones.

The PC1 standard relates to wireless power transmitters and receiversproviding a guaranteed power ranging from 30 W to 150 W. OB correspondsto a mandatory communication channel for PC1, and IB is used forinitialization and link establishment to OB. The wireless powertransmitter may enter an OB handover phase by transmitting a bit-patternfor an OB handover as a response to the configuration packet. Theapplication of the PC1 includes laptop computers or power tools.

The PC2 standard relates to wireless power transmitters and receiversproviding a guaranteed power ranging from 200 W to 2 kW, and itsapplication includes kitchen appliances.

As described above, the PCs may be differentiated in accordance with therespective power levels. And, information on whether or not thecompatibility between the same PCs is supported may be optional ormandatory. Herein, the compatibility between the same PCs indicates thatpower transfer/reception between the same PCs is possible. For example,in case a wireless power transmitter corresponding to PC x is capable ofperforming charging of a wireless power receiver having the same PC x,it may be understood that compatibility is maintained between the samePCs. Similarly, compatibility between different PCs may also besupported. Herein, the compatibility between different PCs indicatesthat power transfer/reception between different PCs is also possible.For example, in case a wireless power transmitter corresponding to PC xis capable of performing charging of a wireless power receiver having PCy, it may be understood that compatibility is maintained between thedifferent PCs.

The support of compatibility between PCs corresponds to an extremelyimportant issue in the aspect of user experience and establishment ofinfrastructure. Herein, however, diverse problems, which will bedescribed below, exist in maintaining the compatibility between PCs.

In case of the compatibility between the same PCs, for example, in caseof a wireless power receiver using a lap-top charging method, whereinstable charging is possible only when power is continuously transferred,even if its respective wireless power transmitter has the same PC, itmay be difficult for the corresponding wireless power receiver to stablyreceive power from a wireless power transmitter of the power toolmethod, which transfers power non-continuously. Additionally, in case ofthe compatibility between different PCs, for example, in case a wirelesspower transmitter having a minimum guaranteed power of 200 W transferspower to a wireless power receiver having a maximum guaranteed power of5 W, the corresponding wireless power receiver may be damaged due to anovervoltage. As a result, it may be inappropriate (or difficult) to usethe PS as an index/reference standard representing/indicating thecompatibility.

Wireless power transmitters and receivers may provide a very convenientuser experience and interface (UX/UI). That is, a smart wirelesscharging service may be provided, and the smart wireless chargingservice may be implemented based on a UX/UI of a smartphone including awireless power transmitter. For these applications, an interface betweena processor of a smartphone and a wireless charging receiver allows for“drop and play” two-way communication between the wireless powertransmitter and the wireless power receiver.

As an example, a user may experience a smart wireless charging servicein a hotel. When the user enters a hotel room and puts a smartphone on awireless charger in the room, the wireless charger transmits wirelesspower to the smartphone and the smartphone receives wireless power. Inthis process, the wireless charger transmits information on the smartwireless charging service to the smartphone. When it is detected thatthe smartphone is located on the wireless charger, when it is detectedthat wireless power is received, or when the smartphone receivesinformation on the smart wireless charging service from the wirelesscharger, the smartphone enters a state of inquiring the user aboutagreement (opt-in) of supplemental features. To this end, the smartphonemay display a message on a screen in a manner with or without an alarmsound. An example of the message may include the phrase “Welcome to ###hotel. Select” “Yes” to activate smart charging functions: “Yes NoThanks.” The smartphone receives an input from the user who selects Yesor No Thanks, and performs a next procedure selected by the user. If Yesis selected, the smartphone transmits corresponding information to thewireless charger. The smartphone and the wireless charger perform thesmart charging function together.

The smart wireless charging service may also include receiving WiFicredentials auto-filled. For example, the wireless charger transmits theWiFi credentials to the smartphone, and the smartphone automaticallyinputs the WiFi credentials received from the wireless charger byrunning an appropriate application.

The smart wireless charging service may also include running a hotelapplication that provides hotel promotions or obtaining remotecheck-in/check-out and contact information.

As another example, the user may experience the smart wireless chargingservice in a vehicle. When the user gets in the vehicle and puts thesmartphone on the wireless charger, the wireless charger transmitswireless power to the smartphone and the smartphone receives wirelesspower. In this process, the wireless charger transmits information onthe smart wireless charging service to the smartphone. When it isdetected that the smartphone is located on the wireless charger, whenwireless power is detected to be received, or when the smartphonereceives information on the smart wireless charging service from thewireless charger, the smartphone enters a state of inquiring the userabout checking identity.

In this state, the smartphone is automatically connected to the vehiclevia WiFi and/or Bluetooth. The smartphone may display a message on thescreen in a manner with or without an alarm sound. An example of themessage may include a phrase of “Welcome to your car. Select “Yes” tosynch device with in-car controls: Yes No Thanks.” Upon receiving theuser's input to select Yes or No Thanks, the smartphone performs a nextprocedure selected by the user. If Yes is selected, the smartphonetransmits corresponding information to the wireless charger. Inaddition, the smartphone and the wireless charger may run an in-vehiclesmart control function together by driving in-vehicleapplication/display software. The user may enjoy the desired music andcheck a regular map location. The in-vehicle applications/displaysoftware may include an ability to provide synchronous access forpassers-by.

As another example, the user may experience smart wireless charging athome. When the user enters the room and puts the smartphone on thewireless charger in the room, the wireless charger transmits wirelesspower to the smartphone and the smartphone receives wireless power. Inthis process, the wireless charger transmits information on the smartwireless charging service to the smartphone. When it is detected thatthe smartphone is located on the wireless charger, when wireless poweris detected to be received, or when the smartphone receives informationon the smart wireless charging service from the wireless charger, thesmartphone enters a state of inquiring the user about agreement (opt-in)of supplemental features. To this end, the smartphone may display amessage on the screen in a manner with or without an alarm sound. Anexample of the message may include a phrase such as “Hi xxx, Would youlike to activate night mode and secure the building?: Yes No Thanks.”The smartphone receives a user input to select Yes or No Thanks andperforms a next procedure selected by the user. If Yes is selected, thesmartphone transmits corresponding information to the wireless charger.The smartphones and the wireless charger may recognize at least user'spattern and recommend the user to lock doors and windows, turn offlights, or set an alarm.

Hereinafter, ‘profiles’ will be newly defined based on indexes/referencestandards representing/indicating the compatibility. More specifically,it may be understood that by maintaining compatibility between wirelesspower transmitters and receivers having the same ‘profile’, stable powertransfer/reception may be performed, and that power transfer/receptionbetween wireless power transmitters and receivers having different‘profiles’ cannot be performed. The ‘profiles’ may be defined inaccordance with whether or not compatibility is possible and/or theapplication regardless of (or independent from) the power class.

For example, the profile may be sorted into 4 different categories, suchas i) Mobile, ii) Power tool, iii) Kitchen, and iv) Wearable.

In case of the ‘Mobile’ profile, the PC may be defined as PC0 and/orPC1, the communication protocol/method may be defined as IB and OBcommunication, and the operation frequency may be defined as 87 to 205kHz, and smartphones, laptop computers, and so on, may exist as theexemplary application.

In case of the ‘Power tool’ profile, the PC may be defined as PC1, thecommunication protocol/method may be defined as IB communication, andthe operation frequency may be defined as 87 to 145 kHz, and powertools, and so on, may exist as the exemplary application.

In case of the ‘Kitchen’ profile, the PC may be defined as PC2, thecommunication protocol/method may be defined as NFC-based communication,and the operation frequency may be defined as less than 100 kHz, andkitchen/home appliances, and so on, may exist as the exemplaryapplication.

In the case of power tools and kitchen profiles, NFC communication maybe used between the wireless power transmitter and the wireless powerreceiver. The wireless power transmitter and the wireless power receivermay confirm that they are NFC devices with each other by exchanging WPCNFC data exchange profile format (NDEF). For example, the WPC NDEF mayinclude an application profile field (e.g., 1B), a version field (e.g.,1B), and profile specific data (e.g., 1B). The application profile fieldindicates whether the corresponding device is i) mobile and computing,ii) power tool, and iii) kitchen, and an upper nibble in the versionfield indicates a major version and a lower nibble indicates a minorversion. In addition, profile-specific data defines content for thekitchen.

In case of the ‘Wearable’ profile, the PC may be defined as PC-1, thecommunication protocol/method may be defined as IB communication, andthe operation frequency may be defined as 87 to 205 kHz, and wearabledevices that are worn by the users, and so on, may exist as theexemplary application.

It may be mandatory to maintain compatibility between the same profiles,and it may be optional to maintain compatibility between differentprofiles.

The above-described profiles (Mobile profile, Power tool profile,Kitchen profile, and Wearable profile) may be generalized and expressedas first to nth profile, and a new profile may be added/replaced inaccordance with the WPC standard and the exemplary embodiment.

In case the profile is defined as described above, the wireless powertransmitter may optionally perform power transfer only to the wirelesspower receiving corresponding to the same profile as the wireless powertransmitter, thereby being capable of performing a more stable powertransfer. Additionally, since the load (or burden) of the wireless powertransmitter may be reduced and power transfer is not attempted to awireless power receiver for which compatibility is not possible, therisk of damage in the wireless power receiver may be reduced.

PC1 of the ‘Mobile’ profile may be defined by being derived from anoptional extension, such as OB, based on PCO. And, the ‘Power tool’profile may be defined as a simply modified version of the PC1 ‘Mobile’profile. Additionally, up until now, although the profiles have beendefined for the purpose of maintaining compatibility between the sameprofiles, in the future, the technology may be evolved to a level ofmaintaining compatibility between different profiles. The wireless powertransmitter or the wireless power receiver may notify (or announce) itsprofile to its counterpart by using diverse methods.

In the AFA standard, the wireless power transmitter is referred to as apower transmitting unit (PTU), and the wireless power receiver isreferred to as a power receiving unit (PRU). And, the PTU is categorizedto multiple classes, as shown in Table 1, and the PRU is categorized tomultiple classes, as shown in Table 2.

TABLE 1 Minimum category Minimum value for a support maximum number ofPTU P_(TX)_IN_MAX requirement supported devices Class 1 2 W 1x Category1 1x Category 1 Class 2 10 W 1x Category 3 2x Category 2 Class 3 16 W 1xCategory 4 2x Category 3 Class 4 33 W 1x Category 5 3x Category 3 Class5 50 W 1x Category 6 4x Category 3 Class 6 70 W 1x Category 7 5xCategory 3

TABLE 2 PRU P_(RX)_OUT_MAX′ Exemplary application Category 1 TBDBluetooth headset Category 2 3.5 W Feature phone Category 3 6.5 WSmartphone Category 4 13 W Tablet PC, Phablet Category 5 25 W Small formfactor laptop Category 6 37.5 W General laptop Category 7 50 W Homeappliance

As shown in Table 1, a maximum output power capability of Class n PTUmay be equal to or greater than the PTX IN MAX of the correspondingclass. The PRU cannot draw a power that is higher than the power levelspecified in the corresponding category.

FIG. 4 a is a block diagram of a wireless power transfer systemaccording to another exemplary embodiment of the present disclosure, andFIG. 4 b is a diagram illustrating an example of a Bluetoothcommunication architecture to which an embodiment according to thepresent disclosure may be applied.

Referring to FIG. 4 a , the wireless power transfer system (10) includesa mobile device (450), which wirelessly receives power, and a basestation (400), which wirelessly transmits power.

As a device providing induction power or resonance power, the basestation (400) may include at least one of a wireless power transmitter(100) and a system unit (405). The wireless power transmitter (100) maytransmit induction power or resonance power and may control thetransmission. The wireless power transmitter (100) may include a powerconversion unit (110) converting electric energy to a power signal bygenerating a magnetic field through a primary coil (or primary coils),and a communications & control unit (120) controlling the communicationand power transfer between the wireless power receiver (200) in order totransfer power at an appropriate (or suitable) level. The system unit(405) may perform input power provisioning, controlling of multiplewireless power transmitters, and other operation controls of the basestation (400), such as user interface control.

The primary coil may generate an electromagnetic field by using analternating current power (or voltage or current). The primary coil issupplied with an alternating current power (or voltage or current) of aspecific frequency, which is being outputted from the power conversionunit (110). And, accordingly, the primary coil may generate a magneticfield of the specific frequency. The magnetic field may be generated ina non-radial shape or a radial shape. And, the wireless power receiver(200) receives the generated magnetic field and then generates anelectric current. In other words, the primary coil wirelessly transmitspower.

In the magnetic induction method, a primary coil and a secondary coilmay have randomly appropriate shapes. For example, the primary coil andthe secondary coil may correspond to copper wire being wound around ahigh-permeability formation, such as ferrite or a non-crystalline metal.The primary coil may also be referred to as a primary core, a primarywinding, a primary loop antenna, and so on. Meanwhile, the secondarycoil may also be referred to as a secondary core, a secondary winding, asecondary loop antenna, a pickup antenna, and so on.

In case of using the magnetic resonance method, the primary coil and thesecondary coil may each be provided in the form of a primary resonanceantenna and a secondary resonance antenna. The resonance antenna mayhave a resonance structure including a coil and a capacitor. At thispoint, the resonance frequency of the resonance antenna may bedetermined by the inductance of the coil and a capacitance of thecapacitor. Herein, the coil may be formed to have a loop shape. And, acore may be placed inside the loop. The core may include a physicalcore, such as a ferrite core, or an air core.

The energy transmission (or transfer) between the primary resonanceantenna and the second resonance antenna may be performed by a resonancephenomenon occurring in the magnetic field. When a near fieldcorresponding to a resonance frequency occurs in a resonance antenna,and in case another resonance antenna exists near the correspondingresonance antenna, the resonance phenomenon refers to a highly efficientenergy transfer occurring between the two resonance antennas that arecoupled with one another. When a magnetic field corresponding to theresonance frequency is generated between the primary resonance antennaand the secondary resonance antenna, the primary resonance antenna andthe secondary resonance antenna resonate with one another. And,accordingly, in a general case, the magnetic field is focused toward thesecond resonance antenna at a higher efficiency as compared to a casewhere the magnetic field that is generated from the primary antenna isradiated to a free space. And, therefore, energy may be transferred tothe second resonance antenna from the first resonance antenna at a highefficiency. The magnetic induction method may be implemented similarlyto the magnetic resonance method. However, in this case, the frequencyof the magnetic field is not required to be a resonance frequency.Nevertheless, in the magnetic induction method, the loops configuringthe primary coil and the secondary coil are required to match oneanother, and the distance between the loops should be very close-ranged.

Although it is not shown in the drawing, the wireless power transmitter(100) may further include a communication antenna. The communicationantenna may transmit and/or receive a communication signal by using acommunication carrier apart from the magnetic field communication. Forexample, the communication antenna may transmit and/or receivecommunication signals corresponding to Wi-Fi, Bluetooth, Bluetooth LE,ZigBee, NFC, and so on.

The communications & control unit (120) may transmit and/or receiveinformation to and from the wireless power receiver (200). Thecommunications & control unit (120) may include at least one of an IBcommunication module and an OB communication module.

The IB communication module may transmit and/or receive information byusing a magnetic wave, which uses a specific frequency as its centerfrequency. For example, the communications & control unit (120) mayperform in-band (TB) communication by transmitting information that iscarried by the magnetic wave through the primary coil or by receivinginformation that is carried by the magnetic wave through the primarycoil. At this point, the communications & control unit (120) may loadinformation in the magnetic wave or may interpret the information thatis carried by the magnetic wave by using a modulation scheme, such asbinary phase shift keying (BPSK) or amplitude shift keying (ASK), and soon, or a coding scheme, such as Manchester coding or non-return-to-zerolevel (NZR-L) coding, and so on. By using the above-described IBcommunication, the communications & control unit (120) may transmitand/or receive information to distances of up to several meters at adata transmission rate of several kbps.

The OB communication module may perform out-of-band communicationthrough a communication antenna. For example, the communications &control unit (120) may be provided to a near field communication module.Examples of the near field communication module may includecommunication modules, such as Wi-Fi, Bluetooth, Bluetooth LE, ZigBee,NFC, and so on.

The communications & control unit (120) may control the overalloperations of the wireless power transmitter (100). The communications &control unit (120) may perform calculation and processing of diverseinformation and may also control each configuration element of thewireless power transmitter (100).

The communications & control unit (120) may be implemented in a computeror a similar device as hardware, software, or a combination of the same.When implemented in the form of hardware, the communications & controlunit (120) may be provided as an electronic circuit performing controlfunctions by processing electrical signals. And, when implemented in theform of software, the communications & control unit (120) may beprovided as a program that operates the communications & control unit(120).

By controlling the operating point, the communications & control unit(120) may control the transmitted power. The operating point that isbeing controlled may correspond to a combination of a frequency (orphase), a duty cycle, a duty ratio, and a voltage amplitude. Thecommunications & control unit (120) may control the transmitted power byadjusting any one of the frequency (or phase), the duty cycle, the dutyratio, and the voltage amplitude. Additionally, the wireless powertransmitter (100) may supply a consistent level of power, and thewireless power receiver (200) may control the level of received power bycontrolling the resonance frequency.

The mobile device (450) includes a wireless power receiver (200)receiving wireless power through a secondary coil, and a load (455)receiving and storing the power that is received by the wireless powerreceiver (200) and supplying the received power to the device.

The wireless power receiver (200) may include a power pick-up unit (210)and a communications & control unit (220). The power pick-up unit (210)may receive wireless power through the secondary coil and may convertthe received wireless power to electric energy. The power pick-up unit(210) rectifies the alternating current (AC) signal, which is receivedthrough the secondary coil, and converts the rectified signal to adirect current (DC) signal. The communications & control unit (220) maycontrol the transmission and reception of the wireless power (transferand reception of power).

The secondary coil may receive wireless power that is being transmittedfrom the wireless power transmitter (100). The secondary coil mayreceive power by using the magnetic field that is generated in theprimary coil. Herein, in case the specific frequency corresponds aresonance frequency, magnetic resonance may occur between the primarycoil and the secondary coil, thereby allowing power to be transferredwith greater efficiency.

Although it is not shown in FIG. 4 a , the communications & control unit(220) may further include a communication antenna. The communicationantenna may transmit and/or receive a communication signal by using acommunication carrier apart from the magnetic field communication. Forexample, the communication antenna may transmit and/or receivecommunication signals corresponding to Wi-Fi, Bluetooth, Bluetooth LE,ZigBee, NFC, and so on.

The communications & control unit (220) may transmit and/or receiveinformation to and from the wireless power transmitter (100). Thecommunications & control unit (220) may include at least one of an IBcommunication module and an OB communication module.

The IB communication module may transmit and/or receive information byusing a magnetic wave, which uses a specific frequency as its centerfrequency. For example, the communications & control unit (220) mayperform IB communication by loading information on the magnetic wave andtransmitting it through the secondary coil or by receiving the magneticwave containing information through the secondary coil. At this point,the communications & control unit (120) may load information in themagnetic wave or may interpret the information that is carried by themagnetic wave by using a modulation scheme, such as binary phase shiftkeying (BPSK) or amplitude shift keying (ASK), and so on, or a codingscheme, such as Manchester coding or non-return-to-zero level (NZR-L)coding, and so on. By using the above-described IB communication, thecommunications & control unit (220) may transmit and/or receiveinformation to distances of up to several meters at a data transmissionrate of several kbps.

The OB communication may perform out-of-band communication through acommunication antenna. For example, the communications & control unit(220) may be provided to a near field communication module.

Examples of the near field communication module may includecommunication modules, such as Wi-Fi, Bluetooth, Bluetooth LE, ZigBee,NFC, and so on.

The communications & control unit (220) may control the overalloperations of the wireless power receiver (200). The communications &control unit (220) may perform calculation and processing of diverseinformation and may also control each configuration element of thewireless power receiver (200).

The communications & control unit (220) may be implemented in a computeror a similar device as hardware, software, or a combination of the same.When implemented in the form of hardware, the communications & controlunit (220) may be provided as an electronic circuit performing controlfunctions by processing electrical signals. And, when implemented in theform of software, the communications & control unit (220) may beprovided as a program that operates the communications & control unit(220).

When the communication/control circuit 120 and the communication/controlcircuit 220 are Bluetooth or Bluetooth LE as an OB communication moduleor a short-range communication module, the communication/control circuit120 and the communication/control circuit 220 may each be implementedand operated with a communication architecture as shown in FIG. 4 b.

Referring to FIG. 4 b , an example of a protocol stack of Bluetoothbasic rate (BR)/enhanced data rate (EDR) supporting GATT, and an exampleof Bluetooth low energy (BLE) protocol stack are shown.

Specifically, the Bluetooth BR/EDR protocol stack may include an uppercontrol stack 460 and a lower host stack 470 based on a host controllerinterface (HCI) 18.

The host stack (or host module) 470 refers to hardware for transmittingor receiving a Bluetooth packet to or from a wirelesstransmission/reception module which receives a Bluetooth signal of 2.4GHz, and the controller stack 460 is connected to the Bluetooth moduleto control the Bluetooth module and perform an operation.

The host stack 470 may include a BR/EDR PHY layer 12, a BR/EDR basebandlayer 14, and a link manager layer 16.

The BR/EDR PHY layer 12 is a layer that transmits and receives a 2.4 GHzradio signal, and in the case of using Gaussian frequency shift keying(GFSK) modulation, the BR/EDR PHY layer 12 may transmit data by hopping79 RF channels.

The BR/EDR baseband layer 14 serves to transmit a digital signal,selects a channel sequence for hopping 1400 times per second, andtransmits a time slot with a length of 625 us for each channel.

The link manager layer 16 controls an overall operation (link setup,control, security) of Bluetooth connection by utilizing a link managerprotocol (LMP).

The link manager layer 16 may perform the following functions.

Performs ACL/SCO logical transport, logical link setup, and control.

Detach: It interrupts connection and informs a counterpart device abouta reason for the interruption.

Performs power control and role switch.

Performs security (authentication, pairing, encryption) function.

The host controller interface layer 18 provides an interface between ahost module and a controller module so that a host provides commands anddata to the controller and the controller provides events and data tothe host.

The host stack (or host module, 470) includes a logical link control andadaptation protocol (L2CAP) 21, an attribute protocol 22, a genericattribute profile (GATT) 23, a generic access profile (GAP) 24, and aBR/EDR profile 25.

The logical link control and adaptation protocol (L2CAP) 21 may provideone bidirectional channel for transmitting data to a specific protocolor profile.

The L2CAP 21 may multiplex various protocols, profiles, etc., providedfrom upper Bluetooth.

L2CAP of Bluetooth BR/EDR uses dynamic channels, supports protocolservice multiplexer, retransmission, streaming mode, and providessegmentation and reassembly, per-channel flow control, and errorcontrol.

The generic attribute profile (GATT) 23 may be operable as a protocolthat describes how the attribute protocol 22 is used when services areconfigured. For example, the generic attribute profile 23 may beoperable to specify how ATT attributes are grouped together intoservices and may be operable to describe features associated withservices.

Accordingly, the generic attribute profile 23 and the attributeprotocols (ATT) 22 may use features to describe device's state andservices, how features are related to each other, and how they are used.

The attribute protocol 22 and the BR/EDR profile 25 define a service(profile) using Bluetooth BR/EDR and an application protocol forexchanging these data, and the generic access profile (GAP) 24 definesdevice discovery, connectivity, and security level.

Next, the Bluetooth LE protocol stack includes a controller stack 480operable to process a wireless device interface important in timing anda host stack 490 operable to process high level data.

First, the controller stack 480 may be implemented using a communicationmodule that may include a Bluetooth wireless device, for example, aprocessor module that may include a processing device such as amicroprocessor.

The host stack 490 may be implemented as a part of an OS running on aprocessor module or as an instantiation of a package on the OS.

In some cases, the controller stack and the host stack may be run orexecuted on the same processing device in a processor module.

The controller stack 480 includes a physical layer (PHY) 32, a linklayer 34, and a host controller interface 36.

The physical layer (PHY, wireless transmission/reception module) 32 is alayer that transmits and receives a 2.4 GHz radio signal and usesGaussian frequency shift keying (GFSK) modulation and a frequencyhopping scheme including 40 RF channels.

The link layer 34, which serves to transmit or receive Bluetoothpackets, creates connections between devices after performingadvertising and scanning functions using 3 advertising channels andprovides a function of exchanging data packets of up to 257 bytesthrough 37 data channels.

The host stack includes a generic access profile (GAP) 45, a logicallink control and adaptation protocol (L2CAP, 41), a security manager(SM) 42, and an attribute protocol (ATT) 43, a generic attribute profile(GATT) 44, a generic access profile 45, and an LE profile 46. However,the host stack 490 is not limited thereto and may include variousprotocols and profiles.

The host stack multiplexes various protocols, profiles, etc., providedfrom upper Bluetooth using L2CAP.

First, the logical link control and adaptation protocol (L2CAP) 41 mayprovide one bidirectional channel for transmitting data to a specificprotocol or profile.

The L2CAP 41 may be operable to multiplex data between higher layerprotocols, segment and reassemble packages, and manage multicast datatransmission.

In Bluetooth LE, three fixed channels (one for signaling CH, one forsecurity manager, and one for attribute protocol) are basically used.Also, a dynamic channel may be used as needed.

Meanwhile, a basic channel/enhanced data rate (BR/EDR) uses a dynamicchannel and supports protocol service multiplexer, retransmission,streaming mode, and the like.

The security manager (SM) 42 is a protocol for authenticating devicesand providing key distribution.

The attribute protocol (ATT) 43 defines a rule for accessing data of acounterpart device in a server-client structure. The ATT has thefollowing 6 message types (request, response, command, notification,indication, confirmation).

1) Request and Response message: A request message is a message forrequesting specific information from the client device to the serverdevice, and the response message is a response message to the requestmessage, which is a message transmitted from the server device to theclient device.

2) Command message: It is a message transmitted from the client deviceto the server device in order to indicate a command of a specificoperation. The server device does not transmit a response with respectto the command message to the client device.

3) Notification message: It is a message transmitted from the serverdevice to the client device in order to notify an event, or the like.The client device does not transmit a confirmation message with respectto the notification message to the server device.

4) Indication and confirmation message: It is a message transmitted fromthe server device to the client device in order to notify an event, orthe like. Unlike the notification message, the client device transmits aconfirmation message regarding the indication message to the serverdevice.

In the present disclosure, when the GATT profile using the attributeprotocol (ATT) 43 requests long data, a value regarding a data length istransmitted to allow a client to clearly know the data length, and acharacteristic value may be received from a server by using a universalunique identifier (UUID).

The generic access profile (GAP) 45, a layer newly implemented for theBluetooth LE technology, is used to select a role for communicationbetween Bluetooth LED devices and to control how a multi-profileoperation takes place.

Also, the generic access profile (GAP) 45 is mainly used for devicediscovery, connection generation, and security procedure part, defines ascheme for providing information to a user, and defines types ofattributes as follows.

1) Service: It defines a basic operation of a device by a combination ofbehaviors related to data

2) Include: It defines a relationship between services

3) Characteristics: It is a data value used in a server

4) Behavior: It is a format that may be read by a computer defined by aUUID (value type).

The LE profile 46, including profiles dependent upon the GATT, is mainlyapplied to a Bluetooth LE device. The LE profile 46 may include, forexample, Battery, Time, FindMe, Proximity, Time, Object DeliveryService, and the like, and details of the GATT-based profiles are asfollows.

1) Battery: Battery information exchanging method

2) Time: Time information exchanging method

3) FindMe: Provision of alarm service according to distance

4) Proximity: Battery information exchanging method

5) Time: Time information exchanging method

The generic attribute profile (GATT) 44 may operate as a protocoldescribing how the attribute protocol (ATT) 43 is used when services areconfigured. For example, the GATT 44 may operate to define how ATTattributes are grouped together with services and operate to describefeatures associated with services.

Thus, the GATT 44 and the ATT 43 may use features in order to describestatus and services of a device and describe how the features arerelated and used.

Hereinafter, procedures of the Bluetooth low energy (BLE) technologywill be briefly described.

The BLE procedure may be classified as a device filtering procedure, anadvertising procedure, a scanning procedure, a discovering procedure,and a connecting procedure.

Device Filtering Procedure

The device filtering procedure is a method for reducing the number ofdevices performing a response with respect to a request, indication,notification, and the like, in the controller stack.

When requests are received from all the devices, it is not necessary torespond thereto, and thus, the controller stack may perform control toreduce the number of transmitted requests to reduce power consumption.

An advertising device or scanning device may perform the devicefiltering procedure to limit devices for receiving an advertisingpacket, a scan request or a connection request.

Here, the advertising device refers to a device transmitting anadvertising event, that is, a device performing an advertisement and isalso termed an advertiser.

The scanning device refers to a device performing scanning, that is, adevice transmitting a scan request.

In the BLE, in a case in which the scanning device receives someadvertising packets from the advertising device, the scanning deviceshould transmit a scan request to the advertising device.

However, in a case in which a device filtering procedure is used so ascan request transmission is not required, the scanning device maydisregard the advertising packets transmitted from the advertisingdevice.

Even in a connection request process, the device filtering procedure maybe used. In a case in which device filtering is used in the connectionrequest process, it is not necessary to transmit a response with respectto the connection request by disregarding the connection request.

Advertising Procedure

The advertising device performs an advertising procedure to performundirected broadcast to devices within a region.

Here, the undirected broadcast is advertising toward all the devices,rather than broadcast toward a specific device, and all the devices mayscan advertising to make an supplemental information request or aconnection request.

In contrast, directed advertising may make an supplemental informationrequest or a connection request by scanning advertising for only adevice designated as a reception device.

The advertising procedure is used to establish a Bluetooth connectionwith an initiating device nearby.

Or, the advertising procedure may be used to provide periodicalbroadcast of user data to scanning devices performing listening in anadvertising channel.

In the advertising procedure, all the advertisements (or advertisingevents) are broadcast through an advertisement physical channel.

The advertising devices may receive scan requests from listening devicesperforming listening to obtain additional user data from advertisingdevices. The advertising devices transmit responses with respect to thescan requests to the devices which have transmitted the scan requests,through the same advertising physical channels as the advertisingphysical channels in which the scan requests have been received.

Broadcast user data sent as part of advertising packets are dynamicdata, while the scan response data is generally static data.

The advertisement device may receive a connection request from aninitiating device on an advertising (broadcast) physical channel. If theadvertising device has used a connectable advertising event and theinitiating device has not been filtered according to the devicefiltering procedure, the advertising device may stop advertising andenter a connected mode. The advertising device may start advertisingafter the connected mode.

Scanning Procedure

A device performing scanning, that is, a scanning device performs ascanning procedure to listen to undirected broadcasting of user datafrom advertising devices using an advertising physical channel.

The scanning device transmits a scan request to an advertising devicethrough an advertising physical channel in order to request additionaldata from the advertising device.

The advertising device transmits a scan response as a response withrespect to the scan request, by including additional user data which hasrequested by the scanning device through an advertising physicalchannel.

The scanning procedure may be used while being connected to other BLEdevice in the BLE piconet.

If the scanning device is in an initiator mode in which the scanningdevice may receive an advertising event and initiates a connectionrequest. The scanning device may transmit a connection request to theadvertising device through the advertising physical channel to start aBluetooth connection with the advertising device.

When the scanning device transmits a connection request to theadvertising device, the scanning device stops the initiator modescanning for additional broadcast and enters the connected mode.

Discovering Procedure

Devices available for Bluetooth communication (hereinafter, referred toas “Bluetooth devices”) perform an advertising procedure and a scanningprocedure in order to discover devices located nearby or in order to bediscovered by other devices within a given area.

The discovering procedure is performed asymmetrically. A Bluetoothdevice intending to discover other device nearby is termed a discoveringdevice, and listens to discover devices advertising an advertising eventthat may be scanned. A Bluetooth device which may be discovered by otherdevice and available to be used is termed a discoverable device andpositively broadcasts an advertising event such that it may be scannedby other device through an advertising (broadcast) physical channel.

Both the discovering device and the discoverable device may have alreadybeen connected with other Bluetooth devices in a piconet.

Connecting Procedure

A connecting procedure is asymmetrical, and requests that, while aspecific Bluetooth device is performing an advertising procedure,another Bluetooth device should perform a scanning procedure.

That is, an advertising procedure may be aimed, and as a result, onlyone device may response to the advertising. After a connectableadvertising event is received from an advertising device, a connectingrequest may be transmitted to the advertising device through anadvertising (broadcast) physical channel to initiate connection.

Hereinafter, operational states, that is, an advertising state, ascanning state, an initiating state, and a connection state, in the BLEtechnology will be briefly described.

Advertising State

A link layer (LL) enters an advertising state according to aninstruction from a host (stack). In a case in which the LL is in theadvertising state, the LL transmits an advertising packet data unit(PDU) in advertising events.

Each of the advertising events include at least one advertising PDU, andthe advertising PDU is transmitted through an advertising channel indexin use. After the advertising PDU is transmitted through an advertisingchannel index in use, the advertising event may be terminated, or in acase in which the advertising device may need to secure a space forperforming other function, the advertising event may be terminatedearlier.

Scanning State

The LL enters the scanning state according to an instruction from thehost (stack). In the scanning state, the LL listens to advertisingchannel indices.

The scanning state includes two types: passive scanning and activescanning. Each of the scanning types is determined by the host.

Time for performing scanning or an advertising channel index are notdefined.

During the scanning state, the LL listens to an advertising channelindex in a scan window duration. A scan interval is defined as aninterval between start points of two continuous scan windows.

When there is no collision in scheduling, the LL should listen in orderto complete all the scan intervals of the scan window as instructed bythe host. In each scan window, the LL should scan other advertisingchannel index. The LL uses every available advertising channel index.

In the passive scanning, the LL only receives packets and cannottransmit any packet.

In the active scanning, the LL performs listening in order to be reliedon an advertising PDU type for requesting advertising PDUs andadvertising device-related supplemental information from the advertisingdevice.

Initiating State

The LL enters the initiating state according to an instruction from thehost (stack).

When the LL is in the initiating state, the LL performs listening onadvertising channel indices.

During the initiating state, the LL listens to an advertising channelindex during the scan window interval.

Connection State

When the device performing a connection state, that is, when theinitiating device transmits a CONNECT_REQ PDU to the advertising deviceor when the advertising device receives a CONNECT_REQ PDU from theinitiating device, the LL enters a connection state.

It is considered that a connection is generated after the LL enters theconnection state. However, it is not necessary to consider that theconnection should be established at a point in time at which the LLenters the connection state. The only difference between a newlygenerated connection and an already established connection is a LLconnection supervision timeout value.

When two devices are connected, the two devices play different roles.

An LL serving as a master is termed a master, and an LL serving as aslave is termed a slave. The master adjusts a timing of a connectingevent, and the connecting event refers to a point in time at which themaster and the slave are synchronized.

Hereinafter, packets defined in an Bluetooth interface will be brieflydescribed. BLE devices use packets defined as follows.

Packet Format

The LL has only one packet format used for both an advertising channelpacket and a data channel packet.

Each packet includes four fields of a preamble, an access address, aPDU, and a CRC.

When one packet is transmitted in an advertising physical channel, thePDU may be an advertising channel PDU, and when one packet istransmitted in a data physical channel, the PDU may be a data channelPDU.

Advertising Channel PDU

An advertising channel PDU has a 16-bit header and payload havingvarious sizes.

A PDU type field of the advertising channel PDU included in the heaterindicates PDU types defined in Table 3 below.

TABLE 3 PDU Type Packet Name 0000 ADV_IND 0001 ADV_DIRECT_IND 0010ADV_NON DIRECT_IND 0011 SCAN_REQ 0100 SCAN_RSP 0101 CONNECT_REQ 0110ADV_SCAN_IND 0111-1111 Reserved

Advertising PDU

The following advertising channel PDU types are termed advertising PDUsand used in a specific event.

ADV_IND: Connectable undirected advertising event

ADV_DIRECT_IND: Connectable directed advertising event

ADV_NONCONN_IND: Unconnectable undirected advertising event

ADV_SCAN_IND: Scannable undirected advertising event

The PDUs are transmitted from the LL in an advertising state, andreceived by the LL in a scanning state or in an initiating state.

Scanning PDU

The following advertising channel DPU types are termed scanning PDUs andare used in a state described hereinafter.

SCAN REQ: Transmitted by the LL in a scanning state and received by theLL in an advertising state.

SCAN RSP: Transmitted by the LL in the advertising state and received bythe LL in the scanning state.

Initiating PDU

The following advertising channel PDU type is termed an initiating PDU.

CONNECT_REQ: Transmitted by the LL in the initiating state and receivedby the LL in the advertising state.

Data Channel PDU

The data channel PDU may include a message integrity check (MIC) fieldhaving a 16-bit header and payload having various sizes.

The procedures, states, and packet formats in the BLE technologydiscussed above may be applied to perform the methods proposed in thepresent disclosure.

Referring to FIG. 4 a , the load (455) may correspond to a battery. Thebattery may store energy by using the power that is being outputted fromthe power pick-up unit (210). Meanwhile, the battery is not mandatorilyrequired to be included in the mobile device (450). For example, thebattery may be provided as a detachable external feature. As anotherexample, the wireless power receiver may include an operating means thatmay execute diverse functions of the electronic device instead of thebattery.

As shown in the drawing, although the mobile device (450) is illustratedto be included in the wireless power receiver (200) and the base station(400) is illustrated to be included in the wireless power transmitter(100), in a broader meaning, the wireless power receiver (200) may beidentified (or regarded) as the mobile device (450), and the wirelesspower transmitter (100) may be identified (or regarded) as the basestation (400).

When the communication/control circuit 120 and the communication/controlcircuit 220 include Bluetooth or Bluetooth LE as an OB communicationmodule or a short-range communication module in addition to the IBcommunication module, the wireless power transmitter 100 including thecommunication/control circuit 120 and the wireless power receiver 200including the communication/control circuit 220 may be represented by asimplified block diagram as shown in FIG. 4 c.

FIG. 4 c is a block diagram illustrating a wireless power transfersystem using BLE communication according to an example, and FIG. 4 d isa block diagram illustrating a wireless power transfer system using BLEcommunication according to another example.

Referring to FIG. 4 c , the wireless power transmitter 100 includes apower conversion circuit 110 and a communication/control circuit 120.The communication/control circuit 120 includes an in-band communicationmodule 121 and a BLE communication module 122.

Meanwhile, the wireless power receiver 200 includes a power pickupcircuit 210 and a communication/control circuit 220. Thecommunication/control circuit 220 includes an in-band communicationmodule 221 and a BLE communication module 222.

In one aspect, the BLE communication modules 122 and 222 perform thearchitecture and operation according to FIG. 4 b . For example, the BLEcommunication modules 122 and 222 may be used to establish a connectionbetween the wireless power transmitter 100 and the wireless powerreceiver 200 and exchange control information and packets necessary forwireless power transfer.

In another aspect, the communication/control circuit 120 may beconfigured to operate a profile for wireless charging. Here, the profilefor wireless charging may be GATT using BLE transmission.

Referring to FIG. 4 d , the communication/control circuits 120 and 220respectively include only in-band communication modules 121 and 221, andthe BLE communication modules 122 and 222 may be provided to beseparated from the communication/control circuits 120 and 220.

Hereinafter, the coil or coil unit includes a coil and at least onedevice being approximate to the coil, and the coil or coil unit may alsobe referred to as a coil assembly, a coil cell, or a cell.

Hereinafter, the coil or coil unit includes a coil and at least onedevice being approximate to the coil, and the coil or coil unit may alsobe referred to as a coil assembly, a coil cell, or a cell.

FIG. 5 is a state transition diagram for describing a wireless powertransfer procedure.

Referring to FIG. 5 , the power transfer from the wireless powertransmitter to the wireless power receiver according to an exemplaryembodiment of the present disclosure may be broadly divided into aselection phase (510), a ping phase (520), an identification andconfiguration phase (530), a negotiation phase (540), a calibrationphase (550), a power transfer phase (560), and a renegotiation phase(570).

If a specific error or a specific event is detected when the powertransfer is initiated or while maintaining the power transfer, theselection phase (510) may include a shifting phase (or step)—referencenumerals S501, S502, S504, S508, S510, and S512. Herein, the specificerror or specific event will be specified in the following description.Additionally, during the selection phase (510), the wireless powertransmitter may monitor whether or not an object exists on an interfacesurface. If the wireless power transmitter detects that an object isplaced on the interface surface, the process step may be shifted to theping phase (520). During the selection phase (510), the wireless powertransmitter may transmit an analog ping signal of a very short pulse,and may detect whether or not an object exists within an active area ofthe interface surface based on a current change in the transmitting coilor the primary coil.

In case an object is sensed (or detected) in the selection phase (510),the wireless power transmitter may measure a quality factor of awireless power resonance circuit (e.g., power transfer coil and/orresonance capacitor). According to the exemplary embodiment of thepresent disclosure, during the selection phase (510), the wireless powertransmitter may measure the quality factor in order to determine whetheror not a foreign object exists in the charging area along with thewireless power receiver. In the coil that is provided in the wirelesspower transmitter, inductance and/or components of the series resistancemay be reduced due to a change in the environment, and, due to suchdecrease, a value of the quality factor may also be decreased. In orderto determine the presence or absence of a foreign object by using themeasured quality factor value, the wireless power transmitter mayreceive from the wireless power receiver a reference quality factorvalue, which is measured in advance in a state where no foreign objectis placed within the charging area. The wireless power transmitter maydetermine the presence or absence of a foreign object by comparing themeasured quality factor value with the reference quality factor value,which is received during the negotiation phase (540). However, in caseof a wireless power receiver having a low reference quality factorvalue—e.g., depending upon its type, purpose, characteristics, and soon, the wireless power receiver may have a low reference quality factorvalue—in case a foreign object exists, since the difference between thereference quality factor value and the measured quality factor value issmall (or insignificant), a problem may occur in that the presence ofthe foreign object cannot be easily determined. Accordingly, in thiscase, other determination factors should be further considered, or thepresent or absence of a foreign object should be determined by usinganother method.

According to another exemplary embodiment of the present disclosure, incase an object is sensed (or detected) in the selection phase (510), inorder to determine whether or not a foreign object exists in thecharging area along with the wireless power receiver, the wireless powertransmitter may measure the quality factor value within a specificfrequency area (e.g., operation frequency area). In the coil that isprovided in the wireless power transmitter, inductance and/or componentsof the series resistance may be reduced due to a change in theenvironment, and, due to such decrease, the resonance frequency of thecoil of the wireless power transmitter may be changed (or shifted). Morespecifically, a quality factor peak frequency that corresponds to afrequency in which a maximum quality factor value is measured within theoperation frequency band may be moved (or shifted).

In the ping phase (520), if the wireless power transmitter detects thepresence of an object, the transmitter activates (or Wakes up) areceiver and transmits a digital ping for identifying whether or not thedetected object corresponds to the wireless power receiver. During theping phase (520), if the wireless power transmitter fails to receive aresponse signal for the digital ping—e.g., a signal intensitypacket—from the receiver, the process may be shifted back to theselection phase (510). Additionally, in the ping phase (520), if thewireless power transmitter receives a signal indicating the completionof the power transfer—e.g., charging complete packet—from the receiver,the process may be shifted back to the selection phase (510).

If the ping phase (520) is completed, the wireless power transmitter mayshift to the identification and configuration phase (530) foridentifying the receiver and for collecting configuration and statusinformation.

In the identification and configuration phase (530), if the wirelesspower transmitter receives an unwanted packet (i.e., unexpected packet),or if the wireless power transmitter fails to receive a packet during apredetermined period of time (i.e., out of time), or if a packettransmission error occurs (i.e., transmission error), or if a powertransfer contract is not configured (i.e., no power transfer contract),the wireless power transmitter may shift to the selection phase (510).

The wireless power transmitter may confirm (or verify) whether or notits entry to the negotiation phase (540) is needed based on aNegotiation field value of the configuration packet, which is receivedduring the identification and configuration phase (530). Based on theverified result, in case a negotiation is needed, the wireless powertransmitter enters the negotiation phase (540) and may then perform apredetermined Foreign Object Detection (FOD) procedure. Conversely, incase a negotiation is not needed, the wireless power transmitter mayimmediately enter the power transfer phase (560).

In the negotiation phase (540), the wireless power transmitter mayreceive a Foreign Object Detection (FOD) status packet that includes areference quality factor value. Or, the wireless power transmitter mayreceive an FOD status packet that includes a reference peak frequencyvalue. Alternatively, the wireless power transmitter may receive astatus packet that includes a reference quality factor value and areference peak frequency value. At this point, the wireless powertransmitter may determine a quality coefficient threshold value for FODbased on the reference quality factor value. The wireless powertransmitter may determine a peak frequency threshold value for FOD basedon the reference peak frequency value.

The wireless power transmitter may detect the presence or absence of anFO in the charging area by using the determined quality coefficientthreshold value for FOD and the currently measured quality factor value(i.e., the quality factor value that was measured before the pingphase), and, then, the wireless power transmitter may control thetransmitted power in accordance with the FOD result. For example, incase the FO is detected, the power transfer may be stopped. However, thepresent disclosure will not be limited only to this.

The wireless power transmitter may detect the presence or absence of anFO in the charging area by using the determined peak frequency thresholdvalue for FOD and the currently measured peak frequency value (i.e., thepeak frequency value that was measured before the ping phase), and,then, the wireless power transmitter may control the transmitted powerin accordance with the FOD result. For example, in case the FO isdetected, the power transfer may be stopped. However, the presentdisclosure will not be limited only to this.

In case the FO is detected, the wireless power transmitter may return tothe selection phase (510). Conversely, in case the FO is not detected,the wireless power transmitter may proceed to the calibration phase(550) and may, then, enter the power transfer phase (560). Morespecifically, in case the FO is not detected, the wireless powertransmitter may determine the intensity of the received power that isreceived by the receiving end during the calibration phase (550) and maymeasure power loss in the receiving end and the transmitting end inorder to determine the intensity of the power that is transmitted fromthe transmitting end. In other words, during the calibration phase(550), the wireless power transmitter may estimate the power loss basedon a difference between the transmitted power of the transmitting endand the received power of the receiving end. The wireless powertransmitter according to the exemplary embodiment of the presentdisclosure may calibrate the threshold value for the FOD by applying theestimated power loss.

In the power transfer phase (560), in case the wireless powertransmitter receives an unwanted packet (i.e., unexpected packet), or incase the wireless power transmitter fails to receive a packet during apredetermined period of time (i.e., time-out), or in case a violation ofa predetermined power transfer contract occurs (i.e., power transfercontract violation), or in case charging is completed, the wirelesspower transmitter may shift to the selection phase (510).

Additionally, in the power transfer phase (560), in case the wirelesspower transmitter is required to reconfigure the power transfer contractin accordance with a status change in the wireless power transmitter,the wireless power transmitter may shift to the renegotiation phase(570). At this point, if the renegotiation is successfully completed,the wireless power transmitter may return to the power transfer phase(560).

The above-described power transfer contract may be configured based onthe status and characteristic information of the wireless powertransmitter and receiver. For example, the wireless power transmitterstatus information may include information on a maximum amount oftransmittable power, information on a maximum number of receivers thatmay be accommodated, and so on. And, the receiver status information mayinclude information on the required power, and so on.

FIG. 6 shows a power control method according to an exemplary embodimentof the present disclosure.

As shown in FIG. 6 , in the power transfer phase, by alternating thepower transfer and/or reception and communication, the wireless powertransmitter (100) and the wireless power receiver (200) may control theamount (or size) of the power that is being transferred. The wirelesspower transmitter and the wireless power receiver operate at a specificcontrol point. The control point indicates a combination of the voltageand the electric current that are provided from the output of thewireless power receiver, when the power transfer is performed.

More specifically, the wireless power receiver selects a desired controlpoint, a desired output current/voltage, a temperature at a specificlocation of the mobile device, and so on, and additionally determines anactual control point at which the receiver is currently operating. Thewireless power receiver calculates a control error value by using thedesired control point and the actual control point, and, then, thewireless power receiver may transmit the calculated control error valueto the wireless power transmitter as a control error packet.

Also, the wireless power transmitter may configure/control a newoperating point—amplitude, frequency, and duty cycle—by using thereceived control error packet, so as to control the power transfer.Therefore, the control error packet may be transmitted/received at aconstant time interval during the power transfer phase, and, accordingto the exemplary embodiment, in case the wireless power receiverattempts to reduce the electric current of the wireless powertransmitter, the wireless power receiver may transmit the control errorpacket by setting the control error value to a negative number. And, incase the wireless power receiver intends to increase the electriccurrent of the wireless power transmitter, the wireless power receivertransmit the control error packet by setting the control error value toa positive number. During the induction mode, by transmitting thecontrol error packet to the wireless power transmitter as describedabove, the wireless power receiver may control the power transfer.

In the resonance mode, which will hereinafter be described in detail,the device may be operated by using a method that is different from theinduction mode. In the resonance mode, one wireless power transmittershould be capable of serving a plurality of wireless power receivers atthe same time. However, in case of controlling the power transfer justas in the induction mode, since the power that is being transferred iscontrolled by a communication that is established with one wirelesspower receiver, it may be difficult to control the power transfer ofadditional wireless power receivers. Therefore, in the resonance modeaccording to the present disclosure, a method of controlling the amountof power that is being received by having the wireless power transmittercommonly transfer (or transmit) the basic power and by having thewireless power receiver control its own resonance frequency.Nevertheless, even during the operation of the resonance mode, themethod described above in FIG. 6 will not be completely excluded. And,additional control of the transmitted power may be performed by usingthe method of FIG. 6 .

FIG. 7 is a block diagram of a wireless power transmitter according toanother exemplary embodiment of the present disclosure. This may belongto a wireless power transfer system that is being operated in themagnetic resonance mode or the shared mode. The shared mode may refer toa mode performing a several-for-one (or one-to-many) communication andcharging between the wireless power transmitter and the wireless powerreceiver. The shared mode may be implemented as a magnetic inductionmethod or a resonance method.

Referring to FIG. 7 , the wireless power transmitter (700) may includeat least one of a cover (720) covering a coil assembly, a power adapter(730) supplying power to the power transmitter (740), a powertransmitter (740) transmitting wireless power, and a user interface(750) providing information related to power transfer processing andother related information. Most particularly, the user interface (750)may be optionally included or may be included as another user interface(750) of the wireless power transmitter (700).

The power transmitter (740) may include at least one of a coil assembly(760), an impedance matching circuit (770), an inverter (780), acommunication unit (790), and a control unit (710).

The coil assembly (760) includes at least one primary coil generating amagnetic field. And, the coil assembly (760) may also be referred to asa coil cell.

The impedance matching circuit (770) may provide impedance matchingbetween the inverter(780) and the primary coil(s). The impedancematching circuit (770) may generate resonance from a suitable frequencythat boosts the electric current of the primary coil(s). In a multi-coilpower transmitter (740), the impedance matching circuit may additionallyinclude a multiplex that routes signals from the inverter(780) to asubset of the primary coils. The impedance matching circuit(770) mayalso be referred to as a tank circuit.

The impedance matching circuit (770) may include a capacitor, aninductor, and a switching device that switches the connection betweenthe capacitor and the inductor. The impedance matching may be performedby detecting a reflective wave of the wireless power that is beingtransferred (or transmitted) through the coil assembly (760) and byswitching the switching device based on the detected reflective wave,thereby adjusting the connection status of the capacitor or the inductoror adjusting the capacitance of the capacitor or adjusting theinductance of the inductor. In some cases, the impedance matching may becarried out even though the impedance matching circuit (770) is omitted.This specification also includes an exemplary embodiment of the wirelesspower transmitter (700), wherein the impedance matching circuit (770) isomitted.

The inverter (780) may convert a DC input to an AC signal. The inverter(780) may be operated as a half-bridge inverter or a full-bridgeinverter in order to generate a pulse wave and a duty cycle of anadjustable frequency. Additionally, the inverter may include a pluralityof stages in order to adjust input voltage levels.

The communication unit (790) may perform communication with the powerreceiver. The power receiver performs load modulation in order tocommunicate requests and information corresponding to the powertransmitter. Therefore, the power transmitter (740) may use thecommunication unit (790) so as to monitor the amplitude and/or phase ofthe electric current and/or voltage of the primary coil in order todemodulate the data being transmitted from the power receiver.

Additionally, the power transmitter (740) may control the output powerto that the data may be transferred through the communication unit (790)by using a Frequency Shift Keying (FSK) method, and so on.

The control unit (710) may control communication and power transfer (ordelivery) of the power transmitter (740). The control unit (710) maycontrol the power transfer by adjusting the above-described operatingpoint. The operating point may be determined by, for example, at leastany one of the operation frequency, the duty cycle, and the inputvoltage.

The communication unit (790) and the control unit (710) may each beprovided as a separate unit/device/chipset or may be collectivelyprovided as one unit/device/chipset.

FIG. 8 shows a block diagram of a wireless power receiver according toanother exemplary embodiment of the present disclosure. This may belongto a wireless power transfer system that is being operated in themagnetic resonance mode or the shared mode.

Referring to FIG. 8 , the wireless power receiver (800) may include atleast one of a user interface (820) providing information related topower transfer processing and other related information, a powerreceiver (830) receiving wireless power, a load circuit (840), and abase (850) supporting and covering the coil assembly. Most particularly,the user interface (820) may be optionally included or may be includedas another user interface (820) of the wireless power receiver (800).

The power receiver (830) may include at least one of a power converter(860), an impedance matching circuit (870), a coil assembly (880), acommunication unit (890), and a control unit (810).

The power converter (860) may convert the AC power that is received fromthe secondary coil to a voltage and electric current that are suitablefor the load circuit. According to an exemplary embodiment, the powerconverter (860) may include a rectifier. The rectifier may rectify thereceived wireless power and may convert the power from an alternatingcurrent (AC) to a direct current (DC). The rectifier may convert thealternating current to the direct current by using a diode or atransistor, and, then, the rectifier may smooth the converted current byusing the capacitor and resistance. Herein, a full-wave rectifier, ahalf-wave rectifier, a voltage multiplier, and so on, that areimplemented as a bridge circuit may be used as the rectifier.Additionally, the power converter may adapt a reflected impedance of thepower receiver.

The impedance matching circuit (870) may provide impedance matchingbetween a combination of the power converter (860) and the load circuit(840) and the secondary coil. According to an exemplary embodiment, theimpedance matching circuit may generate a resonance of approximately 100kHz, which may reinforce the power transfer. The impedance matchingcircuit (870) may include a capacitor, an inductor, and a switchingdevice that switches the combination of the capacitor and the inductor.The impedance matching may be performed by controlling the switchingdevice of the circuit that configured the impedance matching circuit(870) based on the voltage value, electric current value, power value,frequency value, and so on, of the wireless power that is beingreceived. In some cases, the impedance matching may be carried out eventhough the impedance matching circuit (870) is omitted. Thisspecification also includes an exemplary embodiment of the wirelesspower receiver (200), wherein the impedance matching circuit (870) isomitted.

The coil assembly (880) includes at least one secondary coil, and,optionally, the coil assembly (880) may further include an elementshielding the metallic part of the receiver from the magnetic field.

The communication unit (890) may perform load modulation in order tocommunicate requests and other information to the power transmitter.

For this, the power receiver (830) may perform switching of theresistance or capacitor so as to change the reflected impedance.

The control unit (810) may control the received power. For this, thecontrol unit (810) may determine/calculate a difference between anactual operating point and a target operating point of the powerreceiver (830). Thereafter, by performing a request for adjusting thereflected impedance of the power transmitter and/or for adjusting anoperating point of the power transmitter, the difference between theactual operating point and the target operating point may beadjusted/reduced. In case of minimizing this difference, an optimalpower reception may be performed.

The communication unit (890) and the control unit (810) may each beprovided as a separate device/chipset or may be collectively provided asone device/chipset.

FIG. 9 shows a communication frame structure according to an exemplaryembodiment of the present disclosure. This may correspond to acommunication frame structure in a shared mode.

Referring to FIG. 9 , in the shared mode, different forms of frames maybe used along with one another. For example, in the shared mode, aslotted frame having a plurality of slots, as shown in (A), and a freeformat frame that does not have a specified format, as shown in (B), maybe used. More specifically, the slotted frame corresponds to a frame fortransmitting short data packets from the wireless power receiver (200)to the wireless power transmitter (100). And, since the free formatframe is not configured of a plurality of slots, the free format framemay correspond to a frame that is capable of performing transmission oflong data packets.

Meanwhile, the slotted frame and the free format frame may be referredto other diverse terms by anyone skilled in the art. For example, theslotted frame may be alternatively referred to as a channel frame, andthe free format frame may be alternatively referred to as a messageframe.

More specifically, the slotted frame may include a sync patternindicating the starting point (or beginning) of a slot, a measurementslot, nine slots, and additional sync patterns each having the same timeinterval that precedes each of the nine slots.

Herein, the additional sync pattern corresponds to a sync pattern thatis different from the sync pattern that indicates the starting point ofthe above-described frame. More specifically, the additional syncpattern does not indicate the starting point of the frame but mayindicate information related to the neighboring (or adjacent) slots(i.e., two consecutive slots positioned on both sides of the syncpattern).

Among the nine slots, each sync pattern may be positioned between twoconsecutive slots. In this case, the sync pattern may provideinformation related to the two consecutive slots.

Additionally, the nine slots and the sync patterns being provided beforeeach of the nine slots may have the same time interval. For example, thenine slots may have a time interval of 50 ms. And, the nine syncpatterns may have a time length of 50 ms.

Meanwhile, the free format frame, as shown in (B) may not have aspecific format apart from the sync pattern indicating the startingpoint of the frame and the measurement slot. More specifically, the freeformat frame is configured to perform a function that is different fromthat of the slotted frame. For example, the free format frame may beused to perform a function of performing communication of long datapackets (e.g., additional owner information packets) between thewireless power transmitter and the wireless power receiver, or, in caseof a wireless power transmitter being configured of multiple coils, toperform a function of selecting any one of the coils.

Hereinafter, a sync pattern that is included in each frame will bedescribed in more detail with reference to the accompanying drawings.

FIG. 10 is a structure of a sync pattern according to an exemplaryembodiment of the present disclosure.

Referring to FIG. 10 , the sync pattern may be configured of a preamble,a start bit, a response field, a type field, an info field, and a paritybit. In FIG. 10 , the start bit is illustrated as ZERO.

More specifically, the preamble is configured of consecutive bits, andall of the bits may be set to 0. In other words, the preamble maycorrespond to bits for matching a time length of the sync pattern.

The number of bits configuring the preamble may be subordinate to theoperation frequency so that the length of the sync pattern may be mostapproximate to 50 ms but within a range that does not exceed 50 ms. Forexample, in case the operation frequency corresponds to 100 kHz, thesync pattern may be configured of two preamble bits, and, in case theoperation frequency corresponds to 105 kHz, the sync pattern may beconfigured of three preamble bits.

The start bit may correspond to a bit that follows the preamble, and thestart bit may indicate ZERO. The ZERO may correspond to a bit thatindicates a type of the sync pattern. Herein, the type of sync patternsmay include a frame sync including information that is related to aframe, and a slot sync including information of the slot. Morespecifically, the sync pattern may be positioned between consecutiveframes and may correspond to a frame sync that indicate a start of theframe, or the sync pattern may be positioned between consecutive slotsamong a plurality of slots configuring the frame and may correspond to async slot including information related to the consecutive slots.

For example, in case the ZERO is equal to 0, this may indicate that thecorresponding slot is a slot sync that is positioned in-between slots.And, in case the ZERO is equal to 1, this may indicate that thecorresponding sync pattern is a frame sync being located in-betweenframes.

A parity bit corresponds to a last bit of the sync pattern, and theparity bit may indicate information on a number of bits configuring thedata fields (i.e., the response field, the type field, and the infofield) that are included in the sync pattern. For example, in case thenumber of bits configuring the data fields of the sync patterncorresponds to an even number, the parity bit may be set to when, and,otherwise (i.e., in case the number of bits corresponds to an oddnumber), the parity bit may be set to 0.

The response field may include response information of the wirelesspower transmitter for its communication with the wireless power receiverwithin a slot prior to the sync pattern. For example, in case acommunication between the wireless power transmitter and the wirelesspower receiver is not detected, the response field may have a value of‘00’. Additionally, if a communication error is detected in thecommunication between the wireless power transmitter and the wirelesspower receiver, the response field may have a value of ‘01’. Thecommunication error corresponds to a case where two or more wirelesspower receivers attempt to access one slot, thereby causing collision tooccur between the two or more wireless power receivers.

Additionally, the response field may include information indicatingwhether or not the data packet has been accurately received from thewireless power receiver. More specifically, in case the wireless powertransmitter has denied the data packet, the response field may have avalue of “10” (10—not acknowledge (NAK)). And, in case the wirelesspower transmitter has confirmed the data packet, the response field mayhave a value of “11” (11—acknowledge (ACK)).

The type field may indicate the type of the sync pattern. Morespecifically, in case the sync pattern corresponds to a first syncpattern of the frame (i.e., as the first sync pattern, in case the syncpattern is positioned before the measurement slot), the type field mayhave a value of ‘1’, which indicates a frame sync.

Additionally, in a slotted frame, in case the sync pattern does notcorrespond to the first sync pattern of the frame, the type field mayhave a value of ‘0’, which indicates a slot sync.

Moreover, the information field may determine the meaning of its valuein accordance with the sync pattern type, which is indicated in the typefield. For example, in case the type field is equal to 1 (i.e., in casethe sync pattern type indicates a frame sync), the meaning of theinformation field may indicate the frame type. More specifically, theinformation field may indicate whether the current frame corresponds toa slotted frame or a free-format frame. For example, in case theinformation field is given a value of ‘00’, this indicates that thecurrent frame corresponds to a slotted frame. And, in case theinformation field is given a value of ‘01’, this indicates that thecurrent frame corresponds to a free-format frame.

Conversely, in case the type field is equal to 0 (i.e., in case the syncpattern type indicates a slot sync), the information field may indicatea state of a next slot, which is positioned after the sync pattern. Morespecifically, in case the next slot corresponds to a slot that isallocated (or assigned) to a specific wireless power receiver, theinformation field is given a value of ‘00’. In case the next slotcorresponds to a slot that is locked, so as to be temporarily used bythe specific wireless power receiver, the information field is given avalue of ‘01’. Alternatively, in case the next slot corresponds to aslot that may be freely used by a random wireless power receiver, theinformation field is given a value of ‘10’.

FIG. 11 shows operation statuses of a wireless power transmitter and awireless power receiver in a shared mode according to an exemplaryembodiment of the present disclosure.

Referring to FIG. 11 , the wireless power receiver operating in theshared mode may be operated in any one of a selection phase (1100), anintroduction phase (1110), a configuration phase (1120), a negotiationphase (1130), and a power transfer phase (1140).

Firstly, the wireless power transmitter according to the exemplaryembodiment of the present disclosure may transmit a wireless powersignal in order to detect the wireless power receiver. Morespecifically, a process of detecting a wireless power receiver by usingthe wireless power signal may be referred to as an Analog ping.

Meanwhile, the wireless power receiver that has received the wirelesspower signal may enter the selection phase (1100). As described above,the wireless power receiver that has entered the selection phase (1100)may detect the presence or absence of an FSK signal within the wirelesspower signal.

In other words, the wireless power receiver may perform communication byusing any one of an exclusive mode and a shared mode in accordance withthe presence or absence of the FSK signal.

More specifically, in case the FSK signal is included in the wirelesspower signal, the wireless power receiver may operate in the sharedmode, and, otherwise, the wireless power receiver may operate in theexclusive mode.

In case the wireless power receiver operates in the shared mode, thewireless power receiver may enter the introduction phase (1110). In theintroduction phase (1110), the wireless power receiver may transmit acontrol information (CI) packet to the wireless power transmitter inorder to transmit the control information packet during theconfiguration phase, the negotiation phase, and the power transferphase. The control information packet may have a header and informationrelated to control. For example, in the control information packet, theheader may correspond to 0X53.

In the introduction phase (1110), the wireless power receiver performsan attempt to request a free slot for transmitting the controlinformation (CI) packet during the following configuration phase,negotiation phase, and power transfer phase. At this point, the wirelesspower receiver selects a free slot and transmits an initial CI packet.If the wireless power transmitter transmits an ACK as a response to thecorresponding CI packet, the wireless power receiver enters theconfiguration phase. If the wireless power transmitter transmits a NACKas a response to the corresponding CI packet, this indicates thatanother wireless power receiver is performing communication through theconfiguration and negotiation phase. In this case, the wireless powerreceiver re-attempts to perform a request for a free slot.

If the wireless power receiver receives an ACK as a response to the CIpacket, the wireless power receiver may determine the position of aprivate slot within the frame by counting the remaining sync slots up tothe initial frame sync. In all of the subsequent slot-based frames, thewireless power receiver transmits the CI packet through thecorresponding slot.

If the wireless power transmitter authorizes the entry of the wirelesspower receiver to the configuration phase, the wireless powertransmitter provides a locked slot series for the exclusive usage of thewireless power receiver. This may ensure the wireless power receiver toproceed to the configuration phase without any collision.

The wireless power receiver transmits sequences of data packets, such astwo identification data packets (IDHI and IDLO), by using the lockedslots. When this phase is completed, the wireless power receiver entersthe negotiation phase. During the negotiation state, the wireless powertransmitter continues to provide the locked slots for the exclusiveusage of the wireless power receiver. This may ensure the wireless powerreceiver to proceed to the negotiation phase without any collision.

The wireless power receiver transmits one or more negotiation datapackets by using the corresponding locked slot, and the transmittednegotiation data packet(s) may be mixed with the private data packets.Eventually, the corresponding sequence is ended (or completed) alongwith a specific request (SRQ) packet. When the corresponding sequence iscompleted, the wireless power receiver enters the power transfer phase,and the wireless power transmitter stops the provision of the lockedslots.

In the power transfer phase, the wireless power receiver performs thetransmission of a CI packet by using the allocated slots and thenreceives the power. The wireless power receiver may include a regulatorcircuit. The regulator circuit may be included in acommunication/control unit. The wireless power receiver mayself-regulate a reflected impedance of the wireless power receiverthrough the regulator circuit. In other words, the wireless powerreceiver may adjust the impedance that is being reflected for an amountof power that is requested by an external load. This may prevent anexcessive reception of power and overheating.

In the shared mode, (depending upon the operation mode) since thewireless power transmitter may not perform the adjustment of power as aresponse to the received CI packet, in this case, control may be neededin order to prevent an overvoltage state.

Hereinafter, authentication between a wireless power transmitter and awireless power receiver will be disclosed.

A wireless power transmission system which uses in-band communicationmay use USB-C authentication. The authentication includes authenticationof the wireless power transmitter by means of the wireless powerreceiver and authentication of the wireless power receiver by means ofthe wireless power transmitter.

FIG. 12 illustrates a wireless charging certificate format according toan embodiment.

Referring to FIG. 12 , the wireless charging certificate format includesa wireless charging standard certificate structure version (Qiauthentication certificate structure version), a reserved bit, a PTx andleaf indicator (PTx leaf), a certificate type, a signature offset, aserial number, an issuer ID, a subject ID, a public key, and asignature.

In the wireless charging certificate format, the PTx and leaf indicatoris separated from the certificate type so as to be allocated to a bitdifferent from that of the certificate type in the same byte B0.

The PTx and leaf indicator indicates whether a corresponding certificateis a leaf certificate together with whether it is for the wireless powertransmitter. That is, the PTx and leaf indicator may indicate whetherthe corresponding certificate is a leaf certificate for the wirelesspower transmitter.

The PTx and leaf indicator may be configured with 1 bit. If the PTx andleaf indicator is 0, it may indicate that the corresponding certificateis not a leaf certificate or is a leaf certificate of the wireless powerreceiver. Otherwise, if the PTx and leaf indicator is 1, it may indicatethat the corresponding certificate is a leaf certificate of the wirelesspower transmitter.

The certificate type may be configured with, for example, 2 bits and mayindicate that the corresponding certificate is any one of a rootcertificate/intermediate certificate/leaf certificate, and may indicateall of them.

The wireless power transmitter may use a capability packet to notify thewireless power receiver whether an authentication function is supported(in case of authentication of the wireless power transmitter by means ofthe wireless power receiver (i.e., authentication of PTx by PRx)).Meanwhile, the wireless power receiver may use a configuration packet tonotify the wireless power transmitter whether an authentication functionis supported (in case of authentication of the wireless power receiverby means of the wireless power transmitter (i.e., authentication of PRxby PTx)). Hereinafter, a structure of indication information (capabilitypacket and configuration packet) on whether an authentication functionis supported will be described in detail.

FIG. 13 illustrates a capability packet structure of a wireless powertransmitter according to an embodiment.

Referring to FIG. 13 , a capability packet in which a correspondingheader value is 0X31 is configured with 3 bytes. A first byte BOincludes Power Class and Guaranteed Power Value. A second byte B1includes Reserved and Potential Power Value. A third byte B2 includesAuthentication Initiator (AI), Authentication responder (AR), Reserved,WPID, and Not Res Sens. Specifically, the AI is configured with 1 bitand for example, when a value thereof is ‘1b’, it indicates that thewireless power transmitter can operate as au authentication initiator.In addition, the AR is configured with 1 bit and for example, when avalue thereof is ‘1b’, it indicates that the wireless power transmittercan operate as an authentication responder.

FIG. 14 illustrates a configuration packet structure of a wireless powerreceiver according to an embodiment.

Referring to FIG. 14 , a configuration packet in which a correspondingheader value is 0X51 is configured with 5 bytes. A first byte BOincludes Power Class and Maximum Power Value. A second byte B1 includesAI, AR, and Reserved. A third byte B2 includes Prop, Reserved, ZERO, andCount. A fourth byte B3 includes Window Size and Window Offset. A fifthbyte B4 includes Neg, Polarity, Depth, Auth, and Reserved. Specifically,the AI is configured with 1 bit and for example, when a value thereof is‘1b’, it indicates that the corresponding wireless power receiveroperates as an authentication initiator. Further, the AR is configuredwith 1 bit and for example, when a value thereof is ‘1b’, it indicatesthat the corresponding wireless power receiver operates as anauthentication responder.

A message used in the authentication procedure is referred to as anauthentication message. The authentication message is used to carryinformation related to authentication. There are two types ofauthentication messages. One is an authentication request and the otheris an authentication response. The authentication request is transmittedby an authentication initiator, and the authentication response istransmitted by an authentication responder. The wireless powertransmitter and receiving device may be the authentication initiator orthe authentication responder. For example, when the wireless powertransmitter is the authentication initiator, the wireless power receiveris the authentication responder, and when the wireless power receiver isthe authentication initiator, the wireless power transmitter is theauthentication responder.

The authentication request message includes GET_DIGESTS (i.e. 4 bytes),GET_CERTIFICATE (i.e. 8 bytes), and CHALLENGE (i.e. 36 bytes).

The authentication response message includes DIGESTS (i.e. 4+32 bytes),CERTIFICATE (i.e. 4+certificate chain (3×512 bytes)=1540 bytes),CHALLENGE AUTH (i.e. 168 bytes), and ERROR (i.e. 4 bytes).

The authentication message may be referred to as an authenticationpacket, or may be referred to as authentication data and authenticationcontrol information. Further, messages such as GET_DIGEST and DIGESTSmay be referred to as a GET_DIGEST packet, a DIGEST packet, or the like.

FIG. 15 illustrates a data stream of an application level between awireless power transmitter and a wireless power receiver according to anembodiment.

Referring to FIG. 15 , the data stream may include an auxiliary datacontrol (ADC) data packet and/or an auxiliary data transport (ADT) datapacket.

The ADC data packet is used to open the data stream. The ADC data packetmay indicate a type of a message included in the stream and the numberof data bytes. Otherwise, the ADT data packet corresponds to sequencesof data including an actual message. An ADC/end data packet is used whenreporting that the stream ends. For example, the maximum number of databytes in a data transmission stream may be limited to 2047.

ACK or NACK is used to report whether the DAC data packet and the ADTdata packet are normally received. Information required for wirelesscharging, such as a control error packet (CEP), a data stream response(DSR) data packet, or the like, may be transmitted during a transmissiontiming of the ADC data packet and the ADT data packet.

Such a data stream structure may be used so that authentication-relatedinformation or information of other application levels istransmitted/received between the wireless power transmitter and thewireless power receiver.

FIG. 16 illustrates a method in which a wireless power transmitter and awireless power receiver exchange data according to an embodiment.

Referring to FIG. 16 , a data packet of an application level, such as anADC data packet, an ADT data packet, a DSR data packet, or the like, istransmitted from the wireless power transmitter to the wireless powerreceiver or transmitted from the wireless power receiver to the wirelesspower transmitter between CEPs, i.e., at a CE interval. In this case,the wireless power transmitter may transmit the data packet to thewireless power receiver by using a frequency shift keying (FSK) scheme,and the wireless power receiver may transmit the data packet to thewireless power transmitter by using an amplitude shift keying (ASK)scheme. The CEP may be transmitted from the wireless power receiver tothe wireless power transmitter with a specific period in a normalsituation, i.e., in a situation where power transmission is performedstably. In the normal situation, the CE interval is set to a fixed valuewhich is any one value between 250 ms and 300 ms.

Meanwhile, a large amount of authentication data shall betransmitted/received for authenticate between the wireless powertransmitter and the wireless power receiver, and in additional to theauthentication, a large amount of data shall also be required when anadditional function is performed through other data. However, in orderfor the large amount of data to be transmitted by exchanging data inthis manner, it is necessary to divide the data into small pieces andtransmit it little by little at each CE interval. Therefore, it takes alot of time to transmit the large amount of data.

FIG. 17 is a flowchart illustrating a process in which a wireless powerreceiver transmits data to a wireless power transmitter.

Referring to FIG. 17 , the wireless power receiver calculates a controlerror (CE) value for power transmitted by the wireless power transmitterin a power transmission step (S1710). In addition, the wireless powerreceiver configures a control error packet (CEP) including thecalculated CE value and transmits the CEP to the wireless powertransmitter (S1720). For example, the wireless power receiver maycalculate the CE value, based on a difference value between powerrequired by the wireless power receiver and power received from thewireless power transmitter. More specifically, the wireless powerreceiver may select a desired control point (i.e., a desired outputcurrent/voltage, a temperature at a specific location of a mobiledevice, etc.), and may additionally determine an actual control point inwhich the device is currently operating. The wireless power receiver maycalculate the CE value by calculating a difference between the desiredcontrol point and the actual control point, and may transmit it to thewireless power transmitter through the CEP.

Meanwhile, in a situation where power is received stably when thewireless power receiver transmits the CEP, the wireless power receivertransmits the CEP at a specific time interval (e.g., a control errorinterval of 250 ms). In this case, the wireless power receiver maytransmit/receive a data packet with respect to the wireless powertransmitter at the control error interval (S1730).

Otherwise, if it is a situation where the wireless power receiver cannotstably receive power, the wireless power transmitter may transmit theCEP at a shorter time interval for stable power reception. However,since the data packet has a fixed size, the data packet cannot betransmitted when the control error interval is short.

FIG. 18 is a flowchart illustrating a process in which a wireless powerreceiver transmits data to a wireless power transmitter according to anembodiment.

Referring to FIG. 18 , the wireless power receiver calculates a CE valuefor power transmitted by the wireless power transmitter in a powertransmission step (S1810), and repeats at a specific interval a processof configuring a CEP including the calculated CE value and transmittingthe CEP to the wireless power transmitter (S1820). In the presentembodiment, the method of FIG. 1 to FIG. 11 may be performed until thewireless power transmitter and the wireless power receiver approach tothe power transmission step and until the CE interval is stabilized.When it is said that the CE interval is stabilized, it means that powertransmission is performed stably. In addition, when it is said that theCE interval is stabilized, it means that there is no problem intransmitting a large amount of data. Therefore, according to the presentdisclosure, the wireless power receiver may confirm whether the CEinterval is stabilized in order to transmit the large amount of data(S1830). If the CE interval is not stabilized, that is, if it is asituation where a load changes suddenly, the wireless power receiver maytransmit/receive the data packet with respect to the wireless powertransmitter at a corresponding CE interval (S1840). A method oftransmitting data in a situation where a load changes suddenly will bedescribed below.

When the CE interval is stabilized, the wireless power receiver mayadjust (change) the CE interval from the old value, i.e., 250 ms, to avalue greater than 250 ms, so that a large amount of data can betransmitted during one CE interval (S1850). Further, when there is achange in the CE interval, the wireless power receiver may transmitinformation on the CE interval to the wireless power transmitter toinform the wireless power transmitter that it is ready to transmit thelarge amount of data. When the wireless power transmitter receives theinformation on the CE interval from the wireless power receiver, basedon this, the CE interval may be adjusted to transmit the large amount ofdata to the wireless power receiver, or a CE timeout may be adjusted toreceive the large amount of data from the wireless power receiver.Herein, the information on the CE interval may include CE intervalchange information, CE timeout change information, CE intervalrestoration information, information on a duration in which the changedCE interval is maintained, or the like.

Meanwhile, a device which starts to adjust the CE interval may be thewireless power transmitter. In this case, when the CE interval isstabilized, the wireless power transmitter may adjust the CE intervalfrom the old value, i.e., 250 ms, to a value greater than 250 ms toprepare to transmit a large amount of data. In addition, the wirelesspower transmitter may transmit information on the changed CE interval tothe wireless power receiver. When the wireless power receiver receivesthe information on the changed CE interval, the CE interval may beadjusted to transmit a large amount of data to the wireless powertransmitter, or a CE timeout may be adjusted to receive the large amountof data from the wireless power transmitter.

Through such a process, the wireless power transmitter or receivingdevice may receive the large amount of data within the changed(increased) CE interval to perform an additional function. Herein, theadditional function performs functions which use the large amount ofdata, and representatively includes an authentication procedure.

The wireless power transmitter of the present embodiment corresponds tothe wireless power transmitter or wireless power transmitter or powertransmitter of FIG. 1 to FIG. 11 . Therefore, an operation of thewireless power transmitter of the present embodiment is implemented byone of or a combination of two or more of respective components of thewireless power transmitter of FIG. 1 to FIG. 11 . For example, anoperation of processing, transmitting, and receiving data (or a packetor a signal) by the wireless power transmitter of the present embodimentmay be performed by the communication/control unit 120. In addition, thewireless power receiver of the present embodiment corresponds to thewireless power receiver, wireless power receiver, or power receiver ofFIG. 1 to FIG. 11 . Therefore, an operation of the wireless powerreceiver of the present embodiment is implemented by one of or acombination of two or more of respective components of the wirelesspower receiver of FIG. 1 to FIG. 11 . For example, an operation ofprocessing, transmitting, and receiving data (or a packet or a signal)by the wireless power receiver of the present embodiment may beperformed by the communication/control unit 220.

For example, in a case where the CE interval is changed by the wirelesspower transmitter, if it is confirmed in power transmission step thatthe CE interval is stabilized while transmitting power to the wirelesspower receiver, the communication/control unit 120 of the wireless powertransmitter may increase the CE interval, and may transmit informationon the increased CE interval to the wireless power receiver. In thiscase, the communication/control unit 220 of the wireless power receivermay increase the CE interval and/or the CE timeout, based on theinformation on the CE interval received through the wireless powertransmitter to prepare for the increased CE interval. Thereafter, thecommunication/control unit 120 may transmit a large amount of dataduring the increased CE interval, and when it is confirmed that thewireless power receiver completely receives the large amount of data,may transmit information for restoring the increased CE interval.

As another example, in a case where the CE interval is changed by thewireless power receiver, if it is confirmed in the power transmissionstep that the CE interval is stabilized while receiving power from thewireless power transmitter, the communication/control unit 220 of thewireless power receiver may increase the CE interval, and may transmitinformation on the increased CE interval to the wireless powertransmitter. Upon receiving the increased CE interval from the wirelesspower receiver, the communication/control unit 120 of the wireless powertransmitter may increase the CE interval and/or the CE timeout toprepare for the increased CE interval. Thereafter, when it is confirmedthat the wireless power transmitter completely receives a large amountof data, the communication/control unit 220 may transmit information forrestoring the CE interval increased temporarily for transmission of thelarge amount of data.

FIG. 19 is a flowchart illustrating a method in which a wireless powertransmitter and a wireless power receiver exchange data according to anembodiment.

Hereinafter, a method of transmitting a large amount of data byadjusting a CE interval of a transmitter and a CEP timeout of a receiverwill be described in a situation where the CE interval is stabilized.Herein, when the transmitter is the wireless power transmitter, thereceiver corresponds to the wireless power receiver, and when thetransmitter is the wireless power receiver, the receiver corresponds tothe wireless power transmitter.

A CEP is a data packet including a control error (CE) value. The CEvalue is a difference value between a value which is set as a target anda value which is currently being transmitted. When power is stablytransmitted, the difference value is close to ‘0’. Therefore, when it issaid that the CE value in the plurality of CEPs is maintained within aspecific range, it means that power transmission is achieved stably. Inthis case, each CEP is transmitted at a specific interval. That is, theCE interval is stabilized. Hereinafter, such a situation is referred toas a normal situation or a stabilization situation. As an example, FIG.19 illustrates a situation where the CEP is transmitted at an intervalof 250 ms in the stabilization situation. In this situation, in orderfor the transmitter to transmit a large amount of data, CE intervalchange information including information for increasing the CE intervalmay be transmitted between a first CEP and a second CEP, that is, withinthe CE interval. The CE interval change information may be transmittedin the form of a data packet of an application level.

A receiver which has received a signal indicating that the CE intervalis increased from 250 ms may adjust a CE timeout to prepare forreceiving a large amount of data. Herein, the receiver may set a lengthof the CE timeout to be longer than a length of the CE interval. Forexample, when a transmitter informs the receiver that the CE interval ischanged to 1000 ms in a situation where the CE interval is set to 250 msand the CE timeout is set to 800 ms, the receiver may change the CEtimeout from 800 ms to 1500 ms. Meanwhile, although it is shown in FIG.19 that the CE interval is increased from 250 ms to 1000 ms for example,the CE interval may be longer than 1000 ms.

If the CE interval is increased, the transmitter may transmit the largeamount of data during the increased CE interval. In addition, if datatransmission is complete, the CE interval change information includingthe information for restoring the CE interval may be transmitted, andthe CE interval may be restored to 250 ms.

Alternatively, when the CE interval change information is transmitted,the transmitter may also transmit information on a duration in which theincreased CE interval is maintained. In this case, the receiver mayrestore the CE interval when a corresponding duration elapses even ifadditional CE interval change information is not received.

Such a procedure makes it possible to adjust a time for falling into atimeout which occurs when the receiver fails to receive the CEP even ifthe transmitter adjusts the CE interval to transmit the large amount ofdata, thereby stably transmitting/receiving the large amount of data. Inaddition, accordingly, a time required until charging can be reducedcompared to the conventional case, and an additional function includingan authentication procedure can be utilized.

FIG. 20 illustrates a case where an inefficient time in which datacannot be transmitted occurs due to a load transient situation.

Induction-type wireless charging is performed according to a standard.When a wireless power receiver is mounted on a wireless powertransmitter, the wireless power transmitter and the wireless powerreceiver are subjected to several steps of FIG. 5 , and then enter intothe power transmission step. In the power transmission step, charging isactually performed, and the power transmission step is continuouslyperformed until the charging is interrupted. In the power transmissionstep, the wireless power receiver calculates a CE value, and transmits aCEP including the CE value to the wireless power transmitter. Thewireless power transmitter calculates a power transmission amount, basedon the CEP received from the wireless power receiver. The process ofcalculating the CE value and transmitting the CEP is performedrepeatedly in the power transmission step. In a normal situation, aninterval of transmitting the CEP is determined as a maximum value (350ms) and a target value (250 ms).

A small CE value results in a small voltage difference between a targetvoltage and a current voltage, which means that a charging amount isclose to the target voltage. Since the wireless power receiver knowsboth the current voltage and the target voltage, if the CE value isgreat, that is, if the voltage difference between the target voltage andthe current voltage is great, the CEP is transmitted often to supplypower stably. Therefore, when a load transient situation occurs, aninterval (i.e., CE interval) between which the wireless power receivertransmits the CEP to the wireless power transmitter is decreased.However, since a size of a data packet transmitted/received between thewireless power transmitter and the wireless power receiver is fixed, ifthe CE interval is not long enough to transmit the data packet, aninefficient time during which data cannot be transmitted occurs untilpower transmission is stabilized.

A situation where a load suddenly changes (the load transient situation)is caused by the wireless power receiver. The load transient situationmay be, for example, when the wireless power receiver such as a mobiledevice moves while charging, when the mobile device changes a chargingamount to 15 W while performing charging of 5W, when transmit powerstrength is determined in a correction step in the beginning ofcharging, when a vibration occurs, when charging is unstable, or thelike. That is, the load may be changed by external disturbances andseveral other factors except for a stable charging state. The loadtransient situation does not last long but appears temporarily. However,a data packet cannot be transmitted efficiently and stably in the loadtransient situation. Therefore, hereinafter, a method for enabling datatransmission even in a situation where a load changes suddenly such as aload transient situation will be described.

FIG. 21 illustrates a method in which a wireless power transmitter and awireless power receiver exchange data in a load transient situationaccording to an embodiment.

Referring to FIG. 21 , when the load transient situation or the likecauses a decrease in a CE interval, a lot of data can be transmittedwithin a shorter period of time than the conventional case if a datapacket is transmitted by adjusting a size of the data packet to a sizethat can be transmitted at a corresponding interval, which makes itpossible to transmit data efficiently.

To this end, when the wireless power receiver transmits the data packetto the wireless power transmitter, since the CEP is transmitted from thewireless power receiver to the wireless power transmitter, the wirelesspower receiver can calculate and predict the CE interval. Therefore,when the CE interval is decreased due to the load transient situation asshown in FIG. 21 , the wireless power receiver may transmit a datapacket shorter in length than the CE interval, so that data can beefficiently and stably transmitted even in the situation where the loadchanges suddenly. However, if the CE interval is too short to transmit adata packet of 1 byte, since a data packet of less than 1 byte cannot betransmitted, the interval may be ignored.

Meanwhile, when the wireless power transmitter transmits the data packetto the wireless power receiver, the wireless power transmitter cannotknow a CE interval since power is changed by receiving a CEP transmittedby the wireless power receiver even if the load transient situationoccurs. Therefore, if the CE interval is decreased, the wireless powertransmitter cannot efficiently transmit the data packet. However, sincea data packet received from the wireless power receiver immediatelybefore a corresponding interval is transmitted by the wireless powerreceiver by calculating the changed (or decreased) CE interval, thewireless power transmitter may predict the changed CE interval, based ona length of the data packet transmitted by the wireless power receiver.Therefore, in the load transient situation, the wireless powertransmitter may transmit data more efficiently and stably by generatinga data packet of which a length is less than or equal to a length of aCE interval as shown in FIG. 21 , based on the length of the data packetreceived previously (e.g., at an immediate previous CE interval) fromthe wireless power receiver.

The wireless power transmitter in the present embodiment described withreference to FIG. 21 corresponds to the wireless power transmitter orwireless power transmitter or power transmitter of FIG. 1 to FIG. 11 .Therefore, an operation of the wireless power transmitter of the presentembodiment is implemented by one of or a combination of two or more ofrespective components of the wireless power transmitter of FIG. 1 toFIG. 11 . For example, an operation of processing, transmitting, andreceiving data (or a packet or a signal) by the wireless powertransmitter of the present embodiment may be performed by thecommunication/control unit 120.

In addition, the wireless power receiver of the present embodimentdescribed with reference to FIG. 21 corresponds to the wireless powerreceiver, wireless power receiver, or power receiver of FIG. 1 to FIG.11 . Therefore, an operation of the wireless power receiver of thepresent embodiment is implemented by one of or a combination of two ormore of respective components of the wireless power receiver of FIG. 1to FIG. 11 . For example, an operation of processing, transmitting, andreceiving data (or a packet or a signal) by the wireless power receiverof the present embodiment may be performed by the communication/controlunit 220.

FIG. 22 is an exemplary diagram illustrating a case in which aninefficient time where a data packet cannot be transmitted occurs due toa load transient situation while a wireless power receiver transmitsdata to a wireless power transmitter, and FIG. 23 is an exemplarydiagram illustrating a method of efficiently transmitting a data packeteven if an inefficient time occurs as shown in FIG. 22 .

Referring to FIG. 22 , the wireless power receiver may transmit a firstCEP within a first CE interval in a power transmission step. In asituation where power is received stably, that is, in a stabilizationsituation, a CE value is closed to ‘0’. FIG. 22 illustrates a case wherea CE value of ‘1’ is transmitted through a first CEP and a second CEPand a CE value of ‘0’ is transmitted through a third CEP in astabilization situation. In the stabilization situation, each CEP may betransmitted at a specific interval. Therefore, the wireless powerreceiver may transmit an ADT header packet and an ADT data packet ateach CE interval in the stabilization situation. The data packet may beconfigured fixedly with a size of 4 bytes. Upon successfully receivingthe data packet from the wireless power receiver, the wireless powertransmitter may transmit ACK to the wireless power receiver at acorresponding CE interval.

As such, if the load transient situation occurs during power is receivedstably, since the wireless power receiver receives power lower thanrequired power, the wireless power receiver decreases a CE intervalwhile increasing a CE value. In an example of FIG. 22 , it isillustrated that the wireless power receiver transmits a fourth CEPhaving a CE value of ‘25’ due to the load transient situation, so thatgreater power is transmitted from the wireless power transmitter, andthus transmits a fifth CEP having a CE value of ‘18’ and thereaftertransmits a sixth CEP having a CE value of ‘9’. In this case, since theCE value of the fourth CEP is ‘25’, the fifth CEP is transmitted at aninterval of 50 ms with respect to the fourth CEP. Since the CE value ofthe fifth CEP is ‘18’, the sixth CEP is transmitted at an interval of100 ms with respect to the fifth CEP. Since the CE value of the sixthCEP is ‘9’, the seventh CEP may be transmitted at an interval of 150 mswith respect to the sixth CEP.

Although it is illustrated in FIG. 22 that the CEP is transmitted at aninterval of 300 ms if the CE value is less than ‘2’, the CEP istransmitted at an interval of 150 ms if the CE value is greater than orequal to ‘2’ and less than ‘10’, the CEP is transmitted at an intervalof 100 ms if the CE value is greater than or equal to ‘10’ and less than‘20’, and the CEP is transmitted at an interval of 50 ms if the CE valueis greater than or equal to ‘20’, it is for exemplary purposes only, andthus the CE interval based on the CE value can be changed optionally.

In this case, since the data packet has a fixed size (or length), thewireless power receiver cannot transmit the data packet to the wirelesspower transmitter between the fourth CEP and the fifth CEP, between thefifth CEP and the sixth CEP, and between the sixth CEP and the seventhCEP. Therefore, according to an embodiment of the present disclosure,the wireless power receiver may adjust the size of the data packet inthe load transient situation as shown in FIG. 23 . That is, the wirelesspower receiver may use the data packet of a variable length.

In the example of FIG. 23 , if the CE interval is 300 ms, that is, ifthe CE value is less than ‘2’, the wireless power receiver may determinethe size of the data packet to 4 bytes. If the CE interval is 150 ms,that is, if the CE value is greater than or equal to ‘2’ and less than‘10’, the size of the data packet may be determined to 2 bytes. If theCE interval is 100 ms, that is, if the CE value is greater than or equalto ‘10’ and less than ‘20’, the size of the data packet may bedetermined to 1 byte. If the CE interval is 50 ms, that is, if the CEvalue is greater than or equal to ‘20’, the size of the data packet maybe determine to 0 bytes. That is, data is not transmitted. As such, inthe present embodiment, the wireless power receiver may determine thelength of the CE interval based on the CE value, and may adjust the sizeof the data packet based on the length of the CE interval.

Meanwhile, when the size of the data packet is adjusted as describedabove, a time of receiving ACK for the data packet from the wirelesspower transmitter may be considered. That is, the wireless powerreceiver may determine the size of the data packet to be transmitted ata corresponding time interval by considering the length of the CEinterval and a time required to receive the ACK from the wireless powertransmitter.

The wireless power receiver of the present embodiment described withreference to FIG. 22 and FIG. 23 corresponds to the wireless powerreceiver, wireless power receiver, or power receiver of FIG. 1 to FIG.11 . Therefore, an operation of the wireless power receiver of thepresent embodiment is implemented by one of or a combination of two ormore of respective components of the wireless power receiver of FIG. 1to FIG. 11 . For example, an operation of processing, transmitting, andreceiving data (or a packet or a signal) by the wireless power receiverof the present embodiment may be performed by the communication/controlunit 220.

FIG. 24 is an exemplary diagram illustrating a case in which aninefficient time where a data packet cannot be transmitted occurs due toa load transient situation while a wireless power transmitter transmitsdata to a wireless power receiver, and FIG. 25 is an exemplary diagramillustrating a method of efficiently transmitting a data packet even ifan inefficient time occurs as shown in FIG. 24 .

FIG. 24 differs from FIG. 22 in that the wireless power transmitterreceives a DSR data packet from the wireless power receiver afterreceiving a CEP from the wireless power receiver and before transmittingthe data packet to the wireless power receiver. The DSR data packet mayinclude ACK/NACK information for the data packet transmitted by thewireless power transmitter at an immediately previous CE interval.

Similarly to FIG. 22 , in case of FIG. 24 , since the data packet has afixed size (or length), the wireless power transmitter cannot transmitthe data packet to the wireless power receiver between the fourth CEPand the fifth CEP, between the fifth CEP and the sixth CEP, and betweenthe sixth CEP and the seventh CEP. Therefore, according to an embodimentof the present disclosure, the wireless power transmitter may adjust thesize of the data packet in the load transient situation as shown in FIG.25 . That is, the wireless power transmitter may use the data packet ofa variable length.

In the example of FIG. 25 , if the CE interval is 300 ms, that is, ifthe CE value is less than ‘2’, the wireless power receiver may determinethe size of the data packet to 4 bytes. If the CE interval is 150 ms,that is, if the CE value is greater than or equal to ‘2’ and less than‘10’, the size of the data packet may be determined to 2 bytes. If theCE interval is 100 ms, that is, if the CE value is greater than or equalto ‘10’ and less than ‘20’, the size of the data packet may bedetermined to 1 byte. If the CE interval is 50 ms, that is, if the CEvalue is greater than or equal to ‘20’, the size of the data packet maybe determine to 0 bytes. That is, data is not transmitted. As such, inthe present embodiment, the wireless power receiver may predict thelength of the CE interval, and may adjust the size of the data packetbased on the length of the CE interval. In this case, the wireless powertransmitter knows a pattern in which the CE interval is changed by thewireless power receiver in a correction step before entering to a powertransmission step, and thus may use this to determine the size of thedata packet.

Meanwhile, when the size of the data packet is adjusted as describedabove, a time required to receive a DSR data packet from the wirelesspower receiver may be considered. That is, the wireless powertransmitter may determine the size of the data packet that can betransmitted at a corresponding time interval by considering the lengthof the CE interval and the size of the DSR packet.

The wireless power transmitter of the present embodiment described withreference to FIG. 23 and FIG. 24 corresponds to the wireless powertransmitter, wireless power transmitter, or power transmitting of FIG. 1to FIG. 11 . Therefore, an operation of the wireless power transmitterof the present embodiment is implemented by one of or a combination oftwo or more of respective components of the wireless power transmitterof FIG. 1 to FIG. 11 . For example, an operation of processing,transmitting, and receiving data (or a packet or a signal) by thewireless power transmitter of the present embodiment may be performed bythe communication/control unit 120.

FIG. 26 is an exemplary diagram illustrating a process in which awireless power transmitter transmits a data packet to a wireless powerreceiver in a load transient situation according to an embodiment.

Referring to FIG. 26 , when a DSR data packet is received after an n-thCEP is received at an n-th CE interval from the wireless power receiver,the wireless power transmitter may configure an n-th data packet ADT(n)with ‘a’ bytes and transmit it to the wireless power receiver. Herein,‘a’ may be any one value in the range of 1 to 7. When the n-th ADT datapacket is successfully received, the wireless power receiver transmitsthe DSR data packet including ACK after transmitting an (n+1)-th CEP.When DSR(ACK) is received at an (n+1)-th CE interval, the wireless powertransmitter may determine that the data packet of ‘a’ bytes has beensuccessfully transmitted, and may configure a data packet ADT(n+1)greater in size than an immediately previous packet (for example, a sizeof (a+1) bytes) and transmit it to the wireless power receiver. However,if there is no response from the wireless power receiver at an (n+2)-thCE interval, the wireless power transmitter may determine thattransmission of the data packet ADT(n) has failed, and may transmit adata packet ADT(n+1) smaller in size than an immediately previous datapacket (e.g., a size of (a−1) bytes) to the wireless power receiverafter receiving an (n+2)-th CEP and DSR(Poll) at the (n+2)-th CEinterval. By continuously repeating such an operation, the wirelesspower transmitter and the wireless power receiver may adaptively adjusta size of the ADT data packet.

The wireless power transmitter in the present embodiment described withreference to FIG. 25 corresponds to the wireless power transmitter orwireless power transmitter or power transmitter of FIG. 1 to FIG. 11 .Therefore, an operation of the wireless power transmitter of the presentembodiment is implemented by one of or a combination of two or more ofrespective components of the wireless power transmitter of FIG. 1 toFIG. 11 . For example, an operation of processing, transmitting, andreceiving data (or a packet or a signal) by the wireless powertransmitter of the present embodiment may be performed by thecommunication/control unit 120.

In addition, the wireless power receiver of the present embodimentdescribed with reference to FIG. 25 corresponds to the wireless powerreceiver, wireless power receiver, or power receiver of FIG. 1 to FIG.11 . Therefore, an operation of the wireless power receiver of thepresent embodiment is implemented by one of or a combination of two ormore of respective components of the wireless power receiver of FIG. 1to FIG. 11 . For example, an operation of processing, transmitting, andreceiving data (or a packet or a signal) by the wireless power receiverof the present embodiment may be performed by the communication/controlunit 220.

Since the wireless power transmitting method and apparatus or thewireless power receiver and method according to an embodiment of thepresent disclosure do not necessarily include all the elements oroperations, the wireless power transmitter and method and the wirelesspower transmitter and method may be performed with the above-mentionedcomponents or some or all of the operations. Also, embodiments of theabove-described wireless power transmitter and method, or receivingapparatus and method may be performed in combination with each other.Also, each element or operation described above is necessarily performedin the order as described, and an operation described later may beperformed prior to an operation described earlier.

The description above is merely illustrating the technical spirit of thepresent disclosure, and various changes and modifications may be made bythose skilled in the art without departing from the essentialcharacteristics of the present disclosure. Therefore, the embodiments ofthe present disclosure described above may be implemented separately orin combination with each other.

Therefore, the embodiments disclosed in the present disclosure areintended to illustrate rather than limit the scope of the presentdisclosure, and the scope of the technical spirit of the presentdisclosure is not limited by these embodiments. The scope of the presentdisclosure should be construed by claims below, and all technicalspirits within a range equivalent to claims should be construed as beingincluded in the right scope of the present disclosure.

What is claimed is:
 1. A wireless power receiver comprising: a powerpickup to receive, from a wireless power transmitter, wireless power;and a communicator/controller configured to: transmit, to the wirelesspower transmitter, a control error packet; and transmit, to the wirelesspower transmitter, a data packet within a control error interval aftertransmitting the control error packet, wherein the control errorinterval is variable within a range, and wherein a size of the datapacket is varied based on the control error interval.
 2. The wirelesspower receiver of claim 1, wherein the data packet is an auxiliary datatransport (ADT) data packet.
 3. A wireless power transmitter comprising:a power converter configured to transmit, to a wireless power receiver,wireless power; and a communicator/controller configured to receive,from the wireless power receiver, a control error packet; and transmit,to the wireless power receiver, a data packet within a control errorinterval after receiving the control error packet, wherein the controlerror interval is variable within a range, and wherein a size of thedata packet is varied based on the control error interval.
 4. Thewireless power transmitter of claim 3, wherein the data packet is anauxiliary data transport (ADT) data packet.